Bonding and Structure Form III Science 2025 PDF

Form III Science 2025 ===================== Bonding and Structure ===================== {#section.BodyText} {#section-1.BodyText} {#section-2.BodyText} {#section-3.BodyText} Name: {#name.BodyText} ===== {#section-4.BodyText} Master {#master.BodyText} ====== {#section-5.BodyText} {#s...

Form III Science 2025 ===================== Bonding and Structure ===================== {#section.BodyText} {#section-1.BodyText} {#section-2.BodyText} {#section-3.BodyText} Name: {#name.BodyText} ===== {#section-4.BodyText} Master {#master.BodyText} ====== {#section-5.BodyText} {#section-6.BodyText} {#section-7.BodyText} {#section-8.BodyText} {#section-9.BodyText} {#section-10.BodyText} {#section-11.BodyText} {#section-12.BodyText} {#section-13.BodyText} {#section-14.BodyText} +-----------------------------------+-----------------------------------+ | **Outcomes** | | +===================================+===================================+ | 1. | **RECALL the use of the** atomic | | | number of an element to write its | | | electron configuration (e.g. | | | 2.8.8). | +-----------------------------------+-----------------------------------+ | 2. | **RECALL that the number of | | | electrons in the outer shell of | | | atoms can be determined by the | | | group number on the Periodic | | | Table.** | +-----------------------------------+-----------------------------------+ | 3. | **DEFINE** an **ion** as a | | | charged atom or group of atoms. | +-----------------------------------+-----------------------------------+ | 4. | **KNOW** that stable ions of the | | | first 20 elements usually have | | | noble gas electron | | | configurations. | +-----------------------------------+-----------------------------------+ | 5. | **DESCRIBE how some ions are | | | formed by the loss or gain of | | | electrons.** | +-----------------------------------+-----------------------------------+ | 6. | **KNOW** the following polyatomic | | | ions including their combining | | | powers**:** | | | | | | - hydroxide | | | | | | - sulfate | | | | | | - carbonate | | | | | | - hydrogencarbonate | | | | | | - nitrate | | | | | | - phosphate | | | | | | - acetate | | | | | | - ammonium | +-----------------------------------+-----------------------------------+ | 7. | **UNDERSTAND** that some metals, | | | including transition metals have | | | variable charges. | | | | | | **NAME** compounds formed by | | | these metals. | +-----------------------------------+-----------------------------------+ | 8. | **APPRECIATE** that *ionic | | | bonding* is the electrostatic | | | attraction between positive and | | | negative ions. | +-----------------------------------+-----------------------------------+ | 9. | **DESCRIBE** the structure of | | | ionic compounds. | +-----------------------------------+-----------------------------------+ | 10. | **EXPLAIN** the properties of | | | ionic compounds, including | | | melting point, conductivity and | | | malleability. | +-----------------------------------+-----------------------------------+ | 11. | **OBSERVE** a demo (or video | | | demo) of the conductivity of an | | | ionic substance when solid and | | | when molten. | +-----------------------------------+-----------------------------------+ | 12. | **USE** the solubility rules to | | | predict the solubility of ionic | | | compounds. | +-----------------------------------+-----------------------------------+ | 13. | **DEFINE** a **molecule** as a | | | finite structure with given | | | number of non-metal atoms of | | | specific elements and give | | | examples of molecules of both | | | simple covalent compounds and | | | gaseous elements. | +-----------------------------------+-----------------------------------+ | 14. | **DEFINE** a *covalent bond* as a | | | shared pair of electrons between | | | two atoms. | +-----------------------------------+-----------------------------------+ | 15. | **APPRECIATE** that *covalent | | | bonding* involves the | | | electrostatic attraction between | | | the shared pair of electrons and | | | the nucleus of each atom. | +-----------------------------------+-----------------------------------+ | 16. | **DRAW** Lewis dot diagrams | | | (outer shell electrons only) of | | | common covalent compounds. | +-----------------------------------+-----------------------------------+ | 17. | **EXPLAIN** the properties of | | | covalent compounds, including | | | melting point, conductivity and | | | malleability. | +-----------------------------------+-----------------------------------+ | 18. | **DESCRIBE metallic structure and | | | bonding.** | +-----------------------------------+-----------------------------------+ | 19. | **EXPLAIN** the properties of | | | metals, including melting point, | | | conductivity and malleability. | +-----------------------------------+-----------------------------------+ | 20. | **PERFORM** a practical to | | | identify and compare the chemical | | | properties of ionic, covalent and | | | metallic substances. | +-----------------------------------+-----------------------------------+ | 21. | **DESCRIBE** how the properties | | | of ionic, covalent and metallic | | | substances relate to their uses. | +-----------------------------------+-----------------------------------+ {#section-15.BodyText} Recap: The structure of atoms ============================= {#section-16.BodyText} Although an atom is the smallest part of an element that retains its identity in chemical changes, it is nevertheless made up of even smaller particles. The important sub-atomic particles are protons, neutrons, and electrons. {#although-an-atom-is-the-smallest-part-of-an-element-that-retains-its-identity-in-chemical-changes-it-is-nevertheless-made-up-of-even-smaller-particles.-the-important-sub-atomic-particles-are-protons-neutrons-and-electrons..BodyText} ================================================================================================================================================================================================================================= {#section-17.BodyText} Protons and neutrons are both very dense, and together make up the nucleus of an atom. The nucleus is very small compared to the size of an atom. {#protons-and-neutrons-are-both-very-dense-and-together-make-up-the-nucleus-of-an-atom.-the-nucleus-is-very-small-compared-to-the-size-of-an-atom..BodyText} ================================================================================================================================================= {#section-18.BodyText} The atomic number determines the number of protons in the nucleus of atoms of an element. All atoms of the same element have the same atomic number. The number of protons is equal to the number of electrons in a neutral atom of an element and hence, the proton number also determines chemical behaviour. The number of neutrons may vary to give atoms of the same element with different mass numbers. These atoms are called isotopes. {#the-atomic-number-determines-the-number-of-protons-in-the-nucleus-of-atoms-of-an-element.-all-atoms-of-the-same-element-have-the-same-atomic-number.-the-number-of-protons-is-equal-to-the-number-of-electrons-in-a-neutral-atom-of-an-element-and-hence-the-proton-number-also-determines-chemical-behaviour.-the-number-of-neutrons-may-vary-to-give-atoms-of-the-same-element-with-different-mass-numbers.-these-atoms-are-called-isotopes..BodyText} =============================================================================================================================================================================================================================================================================================================================================================================================================================================== {#section-19.BodyText} +-----------------+-----------------+-----------------+-----------------+ | *Particle* {#pa | *Relative charg | *Relative mass* | *Location* {#lo | | rticle.BodyTex | e* {#relative-c | {#relative-mas | cation.BodyTex | | t} | harge.BodyText | s.BodyText} | t} | | ========== | } | =============== | ========== | | | =============== | | | | | == | | | +=================+=================+=================+=================+ | Proton {#proton | +1 {#section-20 | 1 {#section-21 | Nucleus {#nucle | |.BodyText} |.BodyText} |.BodyText} | us.BodyText} | | ====== | == | = | ======= | +-----------------+-----------------+-----------------+-----------------+ | Neutron {#neutr | 0 {#section-22 | 1 {#section-23 | Nucleus {#nucle | | on.BodyText} |.BodyText} |.BodyText} | us-1.BodyText} | | ======= | = | = | ======= | +-----------------+-----------------+-----------------+-----------------+ | Electron {#elec | -1 {#section-24 | 1/1800 {#sectio | Electron shells | | tron.BodyText} |.BodyText} | n-25.BodyText} | {#electron-she | | ======== | == | ====== | lls.BodyText} | | | | | =============== | +-----------------+-----------------+-----------------+-----------------+ {#section-26.BodyText}  {#see-the-source-image.BodyText} ========================================== {#section-27.BodyText} {#section-28.BodyText} The information concerning the sub-atomic particles of atoms of elements is often represented as follows: {#the-information-concerning-the-sub-atomic-particles-of-atoms-of-elements-is-often-represented-as-follows.BodyText} ========================================================================================================= {#section-29.BodyText} +-----------------------------------+-----------------------------------+ | *Mass number* {#mass-number.Body | *E* , where *E* is the atomic sym | | Text} | bol of the element. {#e-where-e-i | | ============= | s-the-atomic-symbol-of-the-elemen | | | t..BodyText} | | | ================================= | | | =================== | +===================================+===================================+ | *Atomic number* {#atomic-number. | {#section-30.BodyText} | | BodyText} | | | =============== | | +-----------------------------------+-----------------------------------+ {#section-31.BodyText} {#section-32.BodyText} For example: {#for-example.BodyText} ============ {#section-33.BodyText} +-----------------------------------+-----------------------------------+ | *23* {#section-36.BodyText} | *Na* {#na.BodyText} | | ==== | ==== | +===================================+===================================+ | *11* {#section-34.BodyText} | {#section-35.BodyText} | | ==== | | +-----------------------------------+-----------------------------------+ {#section-37.BodyText} Atomic symbol: Na, i.e. sodium {#atomic-symbol-na-i.e.-sodium.BodyText} ============================== Atomic number: 11, i.e. number of protons = 11 {#atomic-number-11-i.e.-number-of-protons-11.BodyText} ============================================== Mass number: 23, i.e. number of protons + number of neutrons = 23 {#mass-number-23-i.e.-number-of-protons-number-of-neutrons-23.BodyText} ================================================================= {#section-38.BodyText} Number of protons \_\_\_ , number of neutrons \_\_\_ , number of electrons \_\_\_ {#number-of-protons-___-number-of-neutrons-___-number-of-electrons-___.BodyText} ================================================================================= Recap: How are electrons arranged in atoms? =========================================== {#section-39.BodyText} +-----------------------------------------------------------------------+ | **RECALL the use of the** atomic number of an element to write its el | | ectron configuration (e.g. 2.8.8). {#recall-the-use-of-the-atomic-num | | ber-of-an-element-to-write-its-electron-configuration-e.g.-2.8.8..Bo | | dyText} | | ===================================================================== | | ================================== | +=======================================================================+ | **RECALL that the number of electrons in the outer shell of atoms can | | be determined by the group number on the Periodic Table.** {#recall- | | that-the-number-of-electrons-in-the-outer-shell-of-atoms-can-be-deter | | mined-by-the-group-number-on-the-periodic-table..BodyText} | | ===================================================================== | | =========================================================== | +-----------------------------------------------------------------------+ {#section-40.BodyText} Electrons are arranged in electron shells, which surround the nucleus. {#electrons-are-arranged-in-electron-shells-which-surround-the-nucleus..BodyText} ====================================================================== {#section-41.BodyText} According to Niels Bohr, a Danish chemist who was awarded the Nobel Prize in Physics in 1922, these electron shells are more appropriately named "energy levels". He proposed that electrons in atoms could only have fixed energies. {#according-to-niels-bohr-a-danish-chemist-who-was-awarded-the-nobel-prize-in-physics-in-1922-these-electron-shells-are-more-appropriately-named-energy-levels.-he-proposed-that-electrons-in-atoms-could-only-have-fixed-energies..BodyText} ===================================================================================================================================================================================================================================== {#section-42.BodyText} The most stable position for the negatively charged electrons is in shell 1 (energy level 1), as close as possible to the positively charged nucleus. For this reason, the electrons fill electron shells from the inside out. {#the-most-stable-position-for-the-negatively-charged-electrons-is-in-shell-1-energy-level-1-as-close-as-possible-to-the-positively-charged-nucleus.-for-this-reason-the-electrons-fill-electron-shells-from-the-inside-out..BodyText} ============================================================================================================================================================================================================================== {#section-43.BodyText} The table below shows the maximum number of electrons in each of Bohr's electron shells (energy levels). {#the-table-below-shows-the-maximum-number-of-electrons-in-each-of-bohrs-electron-shells-energy-levels..BodyText} ======================================================================================================== {#section-44.BodyText} +-----------------------------------+-----------------------------------+ | *Electron shell (energy level)* { | *Maximum number of electrons* {#m | | #electron-shell-energy-level.Bod | aximum-number-of-electrons.BodyT | | yText} | ext} | | =============================== | ============================= | +===================================+===================================+ | 1 {#section-45.BodyText} | 2 {#section-46.BodyText} | | = | = | +-----------------------------------+-----------------------------------+ | 2 {#section-47.BodyText} | 8 {#section-48.BodyText} | | = | = | +-----------------------------------+-----------------------------------+ | 3 {#section-49.BodyText} | 8 {#section-50.BodyText} | | = | = | +-----------------------------------+-----------------------------------+ | 4 {#section-51.BodyText} | - {#section-52.BodyText} | | = | = | +-----------------------------------+-----------------------------------+ {#section-53.BodyText} For example: A calcium atom has 20 protons and 20 electrons. {#for-example-a-calcium-atom-has-20-protons-and-20-electrons..BodyText} ============================================================ {#section-54.BodyText} {#section-55.BodyText} {#section-56.BodyText} {#section-57.BodyText} {#section-58.BodyText} {#section-59.BodyText} {#section-60.BodyText} {#section-61.BodyText} {#section-62.BodyText} {#section-63.BodyText} {#section-64.BodyText} {#section-65.BodyText} {#section-66.BodyText} {#section-67.BodyText} {#section-68.BodyText} {#section-69.BodyText} {#section-70.BodyText} {#section-71.BodyText} {#section-72.BodyText} *Electron structure of a calcium atom* {#electron-structure-of-a-calcium-atom.BodyText} ====================================== {#section-73.BodyText} The electron structure of calcium is written: 2.8.8.2 {#the-electron-structure-of-calcium-is-written-2.8.8.2.BodyText} ===================================================== {#section-74.BodyText} This electron configuration tells us there are 2 electrons in shell 1, 8 electrons in shell 2, 8 electrons in shell 3 and 2 electrons in shell 4. {#this-electron-configuration-tells-us-there-are-2-electrons-in-shell-1-8-electrons-in-shell-2-8-electrons-in-shell-3-and-2-electrons-in-shell-4..BodyText} ================================================================================================================================================= {#section-75.BodyText} There are 2 valence (outer) electrons. {#there-are-2-valence-outer-electrons..BodyText} ====================================== Activity: Electron structure ============================ {#section-76.BodyText} **Complete the table** to give the electron structure and number of valence electrons for each atom. {#complete-the-table-to-give-the-electron-structure-and-number-of-valence-electrons-for-each-atom..BodyText} ==================================================================================================== {#section-77.BodyText} +-------------+-------------+-------------+-------------+-------------+ | *Element* { | *Atomic num | *Group numb | *Electron s | *Number of | | #element.B | ber* {#atom | er* {#group | tructure* { | valence ele | | odyText} | ic-number-1 | -number.Bo | #electron-s | ctrons* {#n | | ========= |.BodyText} | dyText} | tructure.B | umber-of-va | | | =========== | =========== | odyText} | lence-elect | | | ==== | === | =========== | rons.BodyT | | | | | ========= | ext} | | | | | | =========== | | | | | | =========== | | | | | | ======= | +=============+=============+=============+=============+=============+ | Hydrogen {# | 1 {#section | {#section- | {#section- | {#section- | | hydrogen.B | -78.BodyTe | 79.BodyTex | 80.BodyTex | 81.BodyTex | | odyText} | xt} | t} | t} | t} | | ======== | = | | | | +-------------+-------------+-------------+-------------+-------------+ | Helium {#he | 2 {#section | {#section- | {#section- | {#section- | | lium.BodyT | -82.BodyTe | 83.BodyTex | 84.BodyTex | 85.BodyTex | | ext} | xt} | t} | t} | t} | | ====== | = | | | | +-------------+-------------+-------------+-------------+-------------+ | Lithium {#l | 3 {#section | {#section- | {#section- | {#section- | | ithium.Bod | -86.BodyTe | 87.BodyTex | 88.BodyTex | 89.BodyTex | | yText} | xt} | t} | t} | t} | | ======= | = | | | | +-------------+-------------+-------------+-------------+-------------+ | Beryllium { | 4 {#section | {#section- | {#section- | {#section- | | #beryllium | -90.BodyTe | 91.BodyTex | 92.BodyTex | 93.BodyTex | |.BodyText} | xt} | t} | t} | t} | | ========= | = | | | | +-------------+-------------+-------------+-------------+-------------+ | Boron {#bor | 5 {#section | {#section- | {#section- | {#section- | | on.BodyTex | -94.BodyTe | 95.BodyTex | 96.BodyTex | 97.BodyTex | | t} | xt} | t} | t} | t} | | ===== | = | | | | +-------------+-------------+-------------+-------------+-------------+ | Carbon {#ca | 6 {#section | {#section- | {#section- | {#section- | | rbon.BodyT | -98.BodyTe | 99.BodyTex | 100.BodyTe | 101.BodyTe | | ext} | xt} | t} | xt} | xt} | | ====== | = | | | | +-------------+-------------+-------------+-------------+-------------+ | Nitrogen {# | 7 {#section | {#section- | {#section- | {#section- | | nitrogen.B | -102.BodyT | 103.BodyTe | 104.BodyTe | 105.BodyTe | | odyText} | ext} | xt} | xt} | xt} | | ======== | = | | | | +-------------+-------------+-------------+-------------+-------------+ | Oxygen {#ox | 8 {#section | {#section- | {#section- | {#section- | | ygen.BodyT | -106.BodyT | 107.BodyTe | 108.BodyTe | 109.BodyTe | | ext} | ext} | xt} | xt} | xt} | | ====== | = | | | | +-------------+-------------+-------------+-------------+-------------+ | Fluorine {# | 9 {#section | {#section- | {#section- | {#section- | | fluorine.B | -110.BodyT | 111.BodyTe | 112.BodyTe | 113.BodyTe | | odyText} | ext} | xt} | xt} | xt} | | ======== | = | | | | +-------------+-------------+-------------+-------------+-------------+ | Neon {#neon | 10 {#sectio | {#section- | {#section- | {#section- | |.BodyText} | n-114.Body | 115.BodyTe | 116.BodyTe | 117.BodyTe | | ==== | Text} | xt} | xt} | xt} | | | == | | | | +-------------+-------------+-------------+-------------+-------------+ | Sodium {#so | 11 {#sectio | {#section- | {#section- | {#section- | | dium.BodyT | n-118.Body | 119.BodyTe | 120.BodyTe | 121.BodyTe | | ext} | Text} | xt} | xt} | xt} | | ====== | == | | | | +-------------+-------------+-------------+-------------+-------------+ | Magnesium { | 12 {#sectio | {#section- | {#section- | {#section- | | #magnesium | n-122.Body | 123.BodyTe | 124.BodyTe | 125.BodyTe | |.BodyText} | Text} | xt} | xt} | xt} | | ========= | == | | | | +-------------+-------------+-------------+-------------+-------------+ | Aluminium { | 13 {#sectio | {#section- | {#section- | {#section- | | #aluminium | n-126.Body | 127.BodyTe | 128.BodyTe | 129.BodyTe | |.BodyText} | Text} | xt} | xt} | xt} | | ========= | == | | | | +-------------+-------------+-------------+-------------+-------------+ | Silicon {#s | 14 {#sectio | {#section- | {#section- | {#section- | | ilicon.Bod | n-130.Body | 131.BodyTe | 132.BodyTe | 133.BodyTe | | yText} | Text} | xt} | xt} | xt} | | ======= | == | | | | +-------------+-------------+-------------+-------------+-------------+ | Phosphorus | 15 {#sectio | {#section- | {#section- | {#section- | | {#phosphoru | n-134.Body | 135.BodyTe | 136.BodyTe | 137.BodyTe | | s.BodyText | Text} | xt} | xt} | xt} | | } | == | | | | | ========== | | | | | +-------------+-------------+-------------+-------------+-------------+ | Sulfur {#su | 16 {#sectio | {#section- | {#section- | {#section- | | lfur.BodyT | n-138.Body | 139.BodyTe | 140.BodyTe | 141.BodyTe | | ext} | Text} | xt} | xt} | xt} | | ====== | == | | | | +-------------+-------------+-------------+-------------+-------------+ | Chlorine {# | 17 {#sectio | {#section- | {#section- | {#section- | | chlorine.B | n-142.Body | 143.BodyTe | 144.BodyTe | 145.BodyTe | | odyText} | Text} | xt} | xt} | xt} | | ======== | == | | | | +-------------+-------------+-------------+-------------+-------------+ | Argon {#arg | 18 {#sectio | {#section- | {#section- | {#section- | | on.BodyTex | n-146.Body | 147.BodyTe | 148.BodyTe | 149.BodyTe | | t} | Text} | xt} | xt} | xt} | | ===== | == | | | | +-------------+-------------+-------------+-------------+-------------+ | Potassium { | 19 {#sectio | {#section- | {#section- | {#section- | | #potassium | n-150.Body | 151.BodyTe | 152.BodyTe | 153.BodyTe | |.BodyText} | Text} | xt} | xt} | xt} | | ========= | == | | | | +-------------+-------------+-------------+-------------+-------------+ | Calcium {#c | 20 {#sectio | {#section- | {#section- | {#section- | | alcium.Bod | n-154.Body | 155.BodyTe | 156.BodyTe | 157.BodyTe | | yText} | Text} | xt} | xt} | xt} | | ======= | == | | | | +-------------+-------------+-------------+-------------+-------------+ {#section-158.BodyText} {#section-159.BodyText} **Identify the relationship between the number of valence electrons in an atom and the group** number of the element in the Periodic table. {#identify-the-relationship-between-the-number-of-valence-electrons-in-an-atom-and-the-group-number-of-the-element-in-the-periodic-table..BodyText} =========================================================================================================================================== {#section-160.BodyText} \-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-- {#section-161.BodyText} =============================================================================================================================================================================================================================================================================================================================================================================================================================================================================================================================================================================================================================================== Recap: Drawing electron configurations {#recap-drawing-electron-configurations.BodyText} ====================================== {#section-162.BodyText} It is easy to draw electron configurations of the first 20 atoms if you remember the following rules: {#it-is-easy-to-draw-electron-configurations-of-the-first-20-atoms-if-you-remember-the-following-rules.BodyText} ===================================================================================================== {#section-163.BodyText} 1. The protons and neutrons form the nucleus at the centre. {#the-protons-and-neutrons-form-the-nucleus-at-the-centre..BodyText} ======================================================== 2. Electrons are in electron shells that surround the nucleus. {#electrons-are-in-electron-shells-that-surround-the-nucleus..BodyText} =========================================================== 3. According to the octet rule, the first electron shell can hold a maximum of 2 electrons, the second can hold 8, and the third can also hold 8. {#according-to-the-octet-rule-the-first-electron-shell-can-hold-a-maximum-of-2-electrons-the-second-can-hold-8-and-the-third-can-also-hold-8..BodyText} ============================================================================================================================================== {#section-164.BodyText} **Draw** electron configurations for atoms of the following elements. {#draw-electron-configurations-for-atoms-of-the-following-elements..BodyText} ===================================================================== {#section-165.BodyText} +-----------------------------------+-----------------------------------+ | *Element* {#element-1.BodyText} | *Electron configuration* {#electr | | ========= | on-configuration.BodyText} | | | ======================== | +===================================+===================================+ | hydrogen {#hydrogen-1.BodyText} | {#section-166.BodyText} | | ======== | | +-----------------------------------+-----------------------------------+ | carbon {#carbon-1.BodyText} | {#section-167.BodyText} | | ====== | | +-----------------------------------+-----------------------------------+ | oxygen {#oxygen-1.BodyText} | {#section-168.BodyText} | | ====== | | +-----------------------------------+-----------------------------------+ | sodium {#sodium-1.BodyText} | {#section-169.BodyText} | | ====== | | +-----------------------------------+-----------------------------------+ | chlorine {#chlorine-1.BodyText} | {#section-170.BodyText} | | ======== | | +-----------------------------------+-----------------------------------+ Atoms to ions ============= {#section-171.BodyText} +-----------------------------------------------------------------------+ | **DEFINE** an **ion** as a charged atom or group of atoms. {#define-a | | n-ion-as-a-charged-atom-or-group-of-atoms..BodyText} | | ========================================================== | +=======================================================================+ | **KNOW** that stable ions of the first 20 elements usually have noble | | gas electron configurations. {#know-that-stable-ions-of-the-first-20 | | -elements-usually-have-noble-gas-electron-configurations..BodyText} | | ===================================================================== | | ============================= | +-----------------------------------------------------------------------+ | **DESCRIBE how some ions are formed by the loss or gain of electrons. | | ** {#describe-how-some-ions-are-formed-by-the-loss-or-gain-of-electro | | ns..BodyText} | | ===================================================================== | | == | +-----------------------------------------------------------------------+ {#section-172.BodyText} Atoms are neutral species; they have equal numbers of protons and electrons. {#atoms-are-neutral-species-they-have-equal-numbers-of-protons-and-electrons..BodyText} ============================================================================ {#section-173.BodyText} Ions are charged species; they have unequal numbers of protons and electrons. An ion can be a charged atom or group of atoms. {#ions-are-charged-species-they-have-unequal-numbers-of-protons-and-electrons.-an-ion-can-be-a-charged-atom-or-group-of-atoms..BodyText} ============================================================================================================================= {#section-174.BodyText} **Ions are formed when atoms gain or lose electrons**. {#ions-are-formed-when-atoms-gain-or-lose-electrons..BodyText} ====================================================== {#section-175.BodyText} Example 1: When a sodium atom loses an electron, it becomes a sodium ion. {#example-1-when-a-sodium-atom-loses-an-electron-it-becomes-a-sodium-ion..BodyText} ========================================================================= {#section-176.BodyText} Na Na^+^ + e^--^ {#na-na-e.BodyText} ================ A diagram of a circle with arrows Description automatically generated ===================================================================== *sodium atom* *sodium ion* ========================== Example 2: When a fluorine atom gains an electron, it becomes a fluoride ion. {#example-2-when-a-fluorine-atom-gains-an-electron-it-becomes-a-fluoride-ion..BodyText} ============================================================================= {#section-178.BodyText} F + e^--^ F^--^ {#f-e-f.BodyText} ===============  ============================================================================================ *fluorine atom* *fluoride ion* ============================== A few things to remember: **Metal atoms always lose electrons to form positive ions.** i.e. Na atoms form Na^+^ ions and Mg atoms form Mg^2+^ ions. **Non-metal atoms always gain electrons to form negative ions (except for hydrogen).** i.e. Cl atoms form Cl^--^ ions and O atoms form O^2--^ ions. **Ions have full valence (outer) electron shells** and resemble the electron structure of unreactive noble gases. Activity: Electron configuration diagrams ========================================= {#section-180.BodyText} Complete the electron configuration diagrams for each atom. {#complete-the-electron-configuration-diagrams-for-each-atom..BodyText} =========================================================== +-----------------+-----------------+-----------------+-----------------+ | *Atom* | *Ion* | | | +=================+=================+=================+=================+ | Sodium atom | | Sodium ion | | | | | | | | Protons: | | Protons: | | | | | | | | Electrons: | | Electrons: | | | | | | | | Symbol: | | Symbol: | | +-----------------+-----------------+-----------------+-----------------+ | Magnesium atom | | Magnesium ion | | | | | | | | Protons: | | Protons: | | | | | | | | Electrons: | | Electrons: | | | | | | | | Symbol: | | Symbol: | | +-----------------+-----------------+-----------------+-----------------+ | Aluminium atom | | Aluminium ion | | | | | | | | Protons: | | Protons: | | | | | | | | Electrons: | | Electrons: | | | | | | | | Symbol: | | Symbol: | | +-----------------+-----------------+-----------------+-----------------+ | Chlorine atom | | Chlorine ion | | | | | | | | Protons: | | Protons: | | | | | | | | Electrons: | | Electrons: | | | | | | | | Symbol: | | Symbol: | | +-----------------+-----------------+-----------------+-----------------+ | Oxygen atom | | Oxide ion | | | | | | | | Protons: | | Protons: | | | | | | | | Electrons: | | Electrons: | | | | | | | | Symbol: | | Symbol: | | +-----------------+-----------------+-----------------+-----------------+ | Nitrogen atom | | Nitride ion | | | | | | | | Protons: | | Protons: | | | | | | | | Electrons: | | Electrons: | | | | | | | | Symbol: | | Symbol: | | +-----------------+-----------------+-----------------+-----------------+ Why do ions form? A simple explanation. {#why-do-ions-form-a-simple-explanation..BodyText} ======================================= {#section-181.BodyText} As we have already learnt, atoms are held together by strong attractive forces. Negatively charged electrons are held in place by a strong pull from the positively charged nucleus in the centre of all atoms. {#as-we-have-already-learnt-atoms-are-held-together-by-strong-attractive-forces.-negatively-charged-electrons-are-held-in-place-by-a-strong-pull-from-the-positively-charged-nucleus-in-the-centre-of-all-atoms..BodyText} =============================================================================================================================================================================================================== {#section-182.BodyText} As we move from left to right across a period in the Periodic table, the number of protons in the nucleus increases whilst the distance between the nucleus and the valence electrons barely changes (as the number of occupied electron shells remains the same). This means, as we move from left to right across a period, the force of attraction between the nucleus of an atom and its outer electrons increases. i.e. an oxygen nucleus holds on to its electrons with more force than a lithium nucleus. {#as-we-move-from-left-to-right-across-a-period-in-the-periodic-table-the-number-of-protons-in-the-nucleus-increases-whilst-the-distance-between-the-nucleus-and-the-valence-electrons-barely-changes-as-the-number-of-occupied-electron-shells-remains-the-same.-this-means-as-we-move-from-left-to-right-across-a-period-the-force-of-attraction-between-the-nucleus-of-an-atom-and-its-outer-electrons-increases.-i.e.-an-oxygen-nucleus-holds-on-to-its-electrons-with-more-force-than-a-lithium-nucleus..BodyText} ================================================================================================================================================================================================================================================================================================================================================================================================================================================================================================================ {#section-183.BodyText} Similarly, as we move from top to bottom down a group, the number of electrons in the outer shell remains the same, but the distance between the nucleus and the outer electron increases (because the number of occupied shells increases) so the force of attraction between the nucleus and the outer electrons decreases. {#similarly-as-we-move-from-top-to-bottom-down-a-group-the-number-of-electrons-in-the-outer-shell-remains-the-same-but-the-distance-between-the-nucleus-and-the-outer-electron-increases-because-the-number-of-occupied-shells-increases-so-the-force-of-attraction-between-the-nucleus-and-the-outer-electrons-decreases..BodyText} ============================================================================================================================================================================================================================================================================================================================= {#section-184.BodyText} To summarise, as we move from left to right and from bottom to top across the Periodic table, the force of attraction between the outer electrons and the nucleus increases. Therefore, the elements at the top, right-hand side of the Periodic table, the non-metals are very good at attracting electrons away from other atoms. These have been highlighted on the Periodic table below. {#to-summarise-as-we-move-from-left-to-right-and-from-bottom-to-top-across-the-periodic-table-the-force-of-attraction-between-the-outer-electrons-and-the-nucleus-increases.-therefore-the-elements-at-the-top-right-hand-side-of-the-periodic-table-the-non-metals-are-very-good-at-attracting-electrons-away-from-other-atoms.-these-have-been-highlighted-on-the-periodic-table-below..BodyText} ============================================================================================================================================================================================================================================================================================================================================================================================ {#section-185.BodyText} What does this all mean? When non-metals come into contact with metal atoms, electrons are transferred from the metal to the non-metal and ions are formed. {#what-does-this-all-mean-when-non-metals-come-into-contact-with-metal-atoms-electrons-are-transferred-from-the-metal-to-the-non-metal-and-ions-are-formed..BodyText} =========================================================================================================================================================== {#section-186.BodyText} {#section-187.BodyText} {#section-188.BodyText} {#section-189.BodyText} Remember: {#remember.BodyText} ========= **Metal atoms always lose electrons to form positive ions.** i.e. Na atoms form Na^+^ ions and Mg atoms form Mg^2+^ ions. **Non-metal atoms always gain electrons to form negative ions (except hydrogen).** i.e. Cl atoms form Cl^-^ ions and O atoms form O^2-^ ions. **Ions always have full outer electron shells** and resemble the electron structure of unreactive noble gases. Compounds made up of oppositely charged ions are called ionic compounds. Overall the compound has no electrical charge. The reaction between sodium and chlorine {#the-reaction-between-sodium-and-chlorine.BodyText} ======================================== {#section-190.BodyText} We know, from our previous study in Chemistry, that sodium reacts with chlorine to produce sodium chloride. {#we-know-from-our-previous-study-in-chemistry-that-sodium-reacts-with-chlorine-to-produce-sodium-chloride..BodyText} =========================================================================================================== {#section-191.BodyText} Here is a sodium atom. A sodium atom has 11 protons and 11 electrons. {#here-is-a-sodium-atom.-a-sodium-atom-has-11-protons-and-11-electrons..BodyText} ===================================================================== The attraction between the sodium atom's nucleus and the outer (valence) electron is weak. {#the-attraction-between-the-sodium-atoms-nucleus-and-the-outer-valence-electron-is-weak..BodyText} ========================================================================================== A diagram of a periodic table Description automatically generated *sodium atom* Here is a chlorine atom. A chlorine atom has 17 protons and 17 electrons. {#here-is-a-chlorine-atom.-a-chlorine-atom-has-17-protons-and-17-electrons..BodyText} ========================================================================= The attraction between the chlorine atom's nucleus and the outer (valence) electrons is strong. {#the-attraction-between-the-chlorine-atoms-nucleus-and-the-outer-valence-electrons-is-strong..BodyText} ===============================================================================================  *chlorine atom* When a chlorine atom meets a sodium atom, sodium's outer (valence) electron is transferred to chlorine's outer shell. The transferred electron is more attracted to the chlorine nucleus than the sodium nucleus. A sodium ion and a chloride ion are formed. A diagram of a circle with arrows Description automatically generated *sodium atom chlorine atom sodium ion chloride ion* In general, when metals react with non-metals, all electrons on outer shell of the metal atom(s) are transferred to the outer shell of the non-metal atom(s), such that both ions have a full outer shell of electrons (a noble gas electron configuration). Activity: The formation of ionic compounds ========================================== For each of the following compounds: a. Draw the electronic configuration of the atom b. Work out how many electrons (represented by e^-^) that atom will lose or gain (eg. Na → Na^+^ + e^--^) c. Deduce the formula of the compound remembering that all ionic compounds have no overall electrical charge. ### **Sodium chloride:** ### **Magnesium oxide:** 3. **Calcium chloride:** Ionic compounds =============== A compound is a pure substance consisting of two or more elements chemically bonded in a fixed ratio by mass. {#a-compound-is-a-pure-substance-consisting-of-two-or-more-elements-chemically-bonded-in-a-fixed-ratio-by-mass..BodyText} ============================================================================================================= {#section-197.BodyText} **Ionic compounds are made up of ions.** {#ionic-compounds-are-made-up-of-ions..BodyText} ======================================== {#section-198.BodyText} Sodium chloride is an ionic compound made up of ions. It is a binary compound as it is formed from two elements. Sodium chloride is not just a mixture of sodium and chlorine, otherwise sodium chloride would have the properties of both sodium and chlorine. The properties of the three substances are quite different as can be seen in the table below. {#sodium-chloride-is-an-ionic-compound-made-up-of-ions.-it-is-a-binary-compound-as-it-is-formed-from-two-elements.-sodium-chloride-is-not-just-a-mixture-of-sodium-and-chlorine-otherwise-sodium-chloride-would-have-the-properties-of-both-sodium-and-chlorine.-the-properties-of-the-three-substances-are-quite-different-as-can-be-seen-in-the-table-below..BodyText} ============================================================================================================================================================================================================================================================================================================================================================= {#section-199.BodyText} {#section-200.BodyText} +-----------------+-----------------+-----------------+-----------------+ | *Property* {#pr | Sodium {#sodium | Chlorine {#chlo | Sodium chloride | | operty.BodyTex | -2.BodyText} | rine-2.BodyTex | {#sodium-chlor | | t} | ====== | t} | ide-1.BodyText | | ========== | | ======== | } | | | | | =============== | +=================+=================+=================+=================+ | *Appearance* {# | Silver-grey sol | Green-yellow ga | Colourless cubi | | appearance.Bod | id {#silver-gre | s {#green-yello | c crystals (the | | yText} | y-solid.BodyTe | w-gas.BodyText | y appear white) | | ============ | xt} | } | {#colourless-c | | | =============== | =============== | ubic-crystals-t | | | == | = | hey-appear-whit | | | | | e.BodyText} | | | {#section-201 | {#section-203 | =============== | | |.BodyText} |.BodyText} | =============== | | | | | =============== | | | {#section-202 | Flask Containin | | | |.BodyText} | g Chlorine Phot | {#section-204 | | | | ograph by Scien |.BodyText} | | |  {#s | ining-chlorine- | About the Eleme | | | odium---wikiped | photograph-by-s | nt Sodium](medi | | | ia.BodyText} | cience-photo-li | a/image34.jpeg) | | | =============== | brary.BodyText | {#get-10-facts | | | =============== | } | -about-the-elem | | | =========== | =============== | ent-sodium.Bod | | | | =============== | yText} | | | | =============== | =============== | | | | =============== | =============== | | | | = | =============== | | | | | =============== | +-----------------+-----------------+-----------------+-----------------+ | *Melting point* | 98°C {#c.BodyT | -102°C {#c-1.B | 808°C {#c-2.Bo | | {#melting-poin | ext} | odyText} | dyText} | | t.BodyText} | ==== | ====== | ===== | | =============== | | | | +-----------------+-----------------+-----------------+-----------------+ | *If added to wa | Reacts to produ | Reacts to form | Dissolves to pr | | ter?* {#if-adde | ce hydrogen gas | a bleaching sol | oduce sodium ch | | d-to-water.Bod | {#reacts-to-pr | ution {#reacts- | loride solution | | yText} | oduce-hydrogen- | to-form-a-bleac | {#dissolves-to | | =============== | gas.BodyText} | hing-solution. | -produce-sodium | | ===== | =============== | BodyText} | -chloride-solut | | | =============== | =============== | ion.BodyText} | | | | =============== | =============== | | | | ===== | =============== | | | | | =============== | +-----------------+-----------------+-----------------+-----------------+ | *Malleability* | Malleable {#mal | n/a {#na-1.Bod | Brittle {#britt | | {#malleability | leable.BodyTex | yText} | le.BodyText} | |.BodyText} | t} | === | ======= | | ============== | ========= | | | +-----------------+-----------------+-----------------+-----------------+ | *Electrical con | Conducts electr | Does not conduc | Conducts electr | | ductivity* {#el | icity in all st | t electricity { | icity in liquid | | ectrical-conduc | ates {#conducts | #does-not-condu | and aqueous st | | tivity.BodyTex | -electricity-in | ct-electricity | ates {#conducts | | t} | -all-states.Bo |.BodyText} | -electricity-in | | =============== | dyText} | =============== | -liquid-and-aqu | | ========== | =============== | ============= | eous-states.Bo | | | =============== | | dyText} | | | ==== | | =============== | | | | | =============== | | | | | =============== | | | | | ==== | +-----------------+-----------------+-----------------+-----------------+ {#section-205.BodyText} Writing formulae for ionic compounds ==================================== --------------------------------------------------------------------------------------------------------------------------------------------------------------------- **KNOW** the following polyatomic ions including their combining powers -- hydroxide, sulfate, carbonate, hydrogen carbonate, nitrate, phosphate, acetate, ammonium --------------------------------------------------------------------------------------------------------------------------------------------------------------------- Writing formulae for binary ionic compounds Binary ionic compounds are made up of oppositely charged ions of two elements. They have no overall charge. For example: Sodium chloride is made up of sodium, Na^+^, ions and chloride, Cl^--^, ions. The two ions that make up sodium chloride have equal and opposite charges and therefore a crystal of sodium chloride will contain equal numbers of sodium and chloride ions. The formula of sodium chloride is NaCl. Magnesium chloride is made up of magnesium, Mg^2+^, ions and chloride, Cl^--^, ions. The charge on the magnesium ion is double the charge on the chloride ion and therefore a crystal of magnesium chloride must contain double the number of chloride ions. The formula of magnesium chloride is MgCl~2~. Polyatomic ions Sometimes a group of two or more atoms can be charged. It is not necessary for you to understand how or why this happens, but it is important that you realise that ions are not restricted to the simple type that form from single atoms gaining or losing electrons. The most common examples (and hence the ones you need to become familiar with) are shown below: You will need to learn the formulae for these ions, *Polyatomic ion* *Formula* *Combining power* ------------------- ------------- ------------------- ammonium NH~4~^+^ 1 hydroxide OH^-^ 1 ethanoate/acetate CH~3~COO^-^ 1 nitrate NO~3~^-^ 1 hydrogencarbonate HCO~3~^-^ 1 carbonate CO~3~^2-^ 2 sulfate SO~4~^2-^ 2 phosphate PO~4~^3-^ 3 Magnesium nitrate and sodium carbonate are examples of ionic compounds that contain polyatomic ions. When writing formulae for ionic compounds of this type, it is important to remember that the charge given is the overall charge of the ion (group of atoms). For example: Magnesium nitrate is made up of magnesium, Mg^2+^, ions and nitrate, NO~3~^-^, ions. Therefore, the formula for magnesium nitrate is Mg(NO~3~)~2~. Sodium carbonate is made up of sodium, Na^+^, ions and carbonate, CO~3~^2-^, ions. Therefore, the formula for sodium carbonate is Na~2~CO~3~. Activity: Naming ionic compounds ================================ {#section-206.BodyText} Complete the following table {#complete-the-following-table.BodyText} ============================ {#section-207.BodyText} ----------------- ------------------ *Compound name* *Ionic formula* Ca(HCO~3~)~2(s)~ LiOH~(s)~ NaHCO~3(s)~ Be(NO~3~)~2(s)~ K~2~SO~4(s)~ BeCO~3(s)~ NaNO~3(s)~ Al(NO~3~)~3(s)~ LiNO~3(s)~ NaOH~(s)~ Mg(NO~3~)~2(s)~ Li~2~CO~3(s)~   Be(HCO~3~)~2(s)~   Li~2~CO~3(s)~   Mg(OH)~2(s)~   MgCO~3(s)~   Li~2~SO~4(s)~   Ca(NO~3~)~2(s)~   LiNO~3(s)~   Mg(NO~3~)~2(s)~   NaNO~3(s)~   NaOH~(s)~   Al(OH)~3(s)~ ----------------- ------------------ +-----------------------+-----------------------+-----------------------+ | *Compound name* {#com | *Ions contained* {#io | *Ionic formula* {#ion | | pound-name.BodyText} | ns-contained.BodyTex | ic-formula.BodyText} | | =============== | t} | =============== | | | ================ | | +=======================+=======================+=======================+ | Sodium chloride {#sod | Na^+^ and Cl^-^ {#na- | NaCl {#nacl.BodyText | | ium-chloride-2.BodyT | and-cl-.BodyText} | } | | ext} | =============== | ==== | | =============== | | | +-----------------------+-----------------------+-----------------------+ | Magnesium fluoride {# | {#section-208.BodyT | {#section-209.BodyT | | magnesium-fluoride.B | ext} | ext} | | odyText} | | | | ================== | | | +-----------------------+-----------------------+-----------------------+ | Calcium iodide {#calc | {#section-210.BodyT | {#section-211.BodyT | | ium-iodide.BodyText} | ext} | ext} | | ============== | | | +-----------------------+-----------------------+-----------------------+ | Lithium bromide {#lit | {#section-212.BodyT | {#section-213.BodyT | | hium-bromide.BodyTex | ext} | ext} | | t} | | | | =============== | | | +-----------------------+-----------------------+-----------------------+ | Magnesium oxide {#mag | {#section-214.BodyT | {#section-215.BodyT | | nesium-oxide-1.BodyT | ext} | ext} | | ext} | | | | =============== | | | +-----------------------+-----------------------+-----------------------+ | Aluminium bromide {#a | {#section-216.BodyT | {#section-217.BodyT | | luminium-bromide.Bod | ext} | ext} | | yText} | | | | ================= | | | +-----------------------+-----------------------+-----------------------+ | Calcium nitride {#cal | {#section-218.BodyT | {#section-219.BodyT | | cium-nitride.BodyTex | ext} | ext} | | t} | | | | =============== | | | +-----------------------+-----------------------+-----------------------+ | Aluminium sulfide {#a | {#section-220.BodyT | {#section-221.BodyT | | luminium-sulfide.Bod | ext} | ext} | | yText} | | | | ================= | | | +-----------------------+-----------------------+-----------------------+ | Potassium nitride {#p | {#section-222.BodyT | {#section-223.BodyT | | otassium-nitride.Bod | ext} | ext} | | yText} | | | | ================= | | | +-----------------------+-----------------------+-----------------------+ | Magnesium phosphide { | {#section-224.BodyT | {#section-225.BodyT | | #magnesium-phosphide | ext} | ext} | |.BodyText} | | | | =================== | | | +-----------------------+-----------------------+-----------------------+ | Zinc sulfide {#zinc-s | {#section-226.BodyT | {#section-227.BodyT | | ulfide.BodyText} | ext} | ext} | | ============ | | | +-----------------------+-----------------------+-----------------------+ | Silver iodide {#silve | {#section-228.BodyT | {#section-229.BodyT | | r-iodide.BodyText} | ext} | ext} | | ============= | | | +-----------------------+-----------------------+-----------------------+ | Sodium nitrate {#sodi | {#section-230.BodyT | {#section-231.BodyT | | um-nitrate.BodyText} | ext} | ext} | | ============== | | | +-----------------------+-----------------------+-----------------------+ | Calcium carbonate {#c | {#section-232.BodyT | {#section-233.BodyT | | alcium-carbonate.Bod | ext} | ext} | | yText} | | | | ================= | | | +-----------------------+-----------------------+-----------------------+ | Lithium sulfate {#lit | {#section-234.BodyT | {#section-235.BodyT | | hium-sulfate.BodyTex | ext} | ext} | | t} | | | | =============== | | | +-----------------------+-----------------------+-----------------------+ | Zinc nitrate {#zinc-n | {#section-236.BodyT | {#section-237.BodyT | | itrate.BodyText} | ext} | ext} | | ============ | | | +-----------------------+-----------------------+-----------------------+ | Ammonium chloride {#a | {#section-238.BodyT | {#section-239.BodyT | | mmonium-chloride.Bod | ext} | ext} | | yText} | | | | ================= | | | +-----------------------+-----------------------+-----------------------+ | Magnesium hydroxide { | {#section-240.BodyT | {#section-241.BodyT | | #magnesium-hydroxide | ext} | ext} | |.BodyText} | | | | =================== | | | +-----------------------+-----------------------+-----------------------+ | Calcium hydrogencarbo | {#section-242.BodyT | {#section-243.BodyT | | nate {#calcium-hydrog | ext} | ext} | | encarbonate.BodyText | | | | } | | | | ===================== | | | | ==== | | | +-----------------------+-----------------------+-----------------------+ | Ammonium hydroxide {# | {#section-244.BodyT | {#section-245.BodyT | | ammonium-hydroxide.B | ext} | ext} | | odyText} | | | | ================== | | | +-----------------------+-----------------------+-----------------------+ | Ammonium phosphate {# | {#section-246.BodyT | {#section-247.BodyT | | ammonium-phosphate.B | ext} | ext} | | odyText} | | | | ================== | | | +-----------------------+-----------------------+-----------------------+ Complete the following table {#complete-the-following-table-1.BodyText} ============================ Transition metal ions ===================== +-----------------------------------------------------------------------+ | **UNDERSTAND** that some metals, including transition metals have | | variable charges. | | | | **NAME** compounds formed by these metals. | +-----------------------------------------------------------------------+ Whilst the elements in Group II, for example, only form ions with a 2+ charge, transition metals such as copper can form more than one stable ion. For instance, Cu^+^ and Cu^2+^ are both stable ions and can both be found in compounds. There are two exceptions: zinc only forms Zn^2+^ ions, and silver only forms Ag^+^ ions. periodic table 2006 When a non-metal combines with a transition metal, we need to communicate which ion can be found in the compound. We do this by writing the name of the transition metal, followed by size of the positive charge in roman numerals in brackets after the name. ***Metal ion*** ***Chemical formula*** ***Name*** ----------------- ------------------------ ---------------------- Cu^+^ CuCl Copper(I) chloride Cu^2+^ CuCl~2~ Copper(II) chloride Cu^+^ CuOH Copper(I) hydroxide Cu^2+^ Cu(OH)~2~ Copper(II) hydroxide Activity: Naming Ionic Compounds 2 ================================== {#section-249.BodyText} Complete the following table {#complete-the-following-table-2.BodyText} ============================ {#section-250.BodyText} +-----------------------+-----------------------+-----------------------+ | *Compound name* {#com | *Ions contained* {#io | *Ionic formula* {#ion | | pound-name-1.BodyTex | ns-contained-1.BodyT | ic-formula-1.BodyTex | | t} | ext} | t} | | =============== | ================ | =============== | +=======================+=======================+=======================+ | Iron(III) oxide {#iro | {#section-251.BodyT | {#section-252.BodyT | | niii-oxide.BodyText} | ext} | ext} | | =============== | | | +-----------------------+-----------------------+-----------------------+ | Lead(IV) chloride {#l | {#section-253.BodyT | {#section-254.BodyT | | eadiv-chloride.BodyT | ext} | ext} | | ext} | | | | ================= | | | +-----------------------+-----------------------+-----------------------+ | Zinc sulfide {#zinc-s | {#section-255.BodyT | {#section-256.BodyT | | ulfide-1.BodyText} | ext} | ext} | | ============ | | | +-----------------------+-----------------------+-----------------------+ | Silver iodide {#silve | {#section-257.BodyT | {#section-258.BodyT | | r-iodide-1.BodyText} | ext} | ext} | | ============= | | | +-----------------------+-----------------------+-----------------------+ | Copper(II) sulfate {# | {#section-259.BodyT | {#section-260.BodyT | | copperii-sulfate.Bod | ext} | ext} | | yText} | | | | ================== | | | +-----------------------+-----------------------+-----------------------+ | Iron(II) hydroxide {# | {#section-261.BodyT | {#section-262.BodyT | | ironii-hydroxide.Bod | ext} | ext} | | yText} | | | | ================== | | | +-----------------------+-----------------------+-----------------------+ | Iron(III) oxide {#iro | {#section-263.BodyT | {#section-264.BodyT | | niii-oxide-1.BodyTex | ext} | ext} | | t} | | | | =============== | | | +-----------------------+-----------------------+-----------------------+ | Copper(II) sulfide {# | {#section-265.BodyT | {#section-266.BodyT | | copperii-sulfide.Bod | ext} | ext} | | yText} | | | | ================== | | | +-----------------------+-----------------------+-----------------------+ | Copper(I) oxide {#cop | {#section-267.BodyT | {#section-268.BodyT | | peri-oxide.BodyText} | ext} | ext} | | =============== | | | +-----------------------+-----------------------+-----------------------+ | Iron(III) fluoride {# | {#section-269.BodyT | {#section-270.BodyT | | ironiii-fluoride.Bod | ext} | ext} | | yText} | | | | ================== | | | +-----------------------+-----------------------+-----------------------+ | Iron(II) chloride {#i | {#section-271.BodyT | {#section-272.BodyT | | ronii-chloride.BodyT | ext} | ext} | | ext} | | | | ================= | | | +-----------------------+-----------------------+-----------------------+ Complete the following table {#complete-the-following-table-3.BodyText} ============================ --------------- -------------- Compound name Formula PbO~(s)~ CoF~4(s)~ FeO~(s)~ CuCl~2(s)~ PbS~(s)~ PbO~2(s)~ FeF~2(s)~ Fe~2~S~3(s)~ FeCl~3(s)~ ZnCl~2(s)~ --------------- -------------- Structure and bonding of ionic compounds ======================================== **APPRECIATE** that *ionic bonding* is the electrostatic attraction between positive and negative ions. --------------------------------------------------------------------------------------------------------- **DESCRIBE** the structure of ionic compounds. Structure in chemistry refers to the special arrangement of the particles that make up a chemical substance. All ionic compounds are made up of positive and negative ions. The positive ions are attracted to the negative ions and the negative ions are attracted to the positive ions. As a result, the positive and negative ions are arranged in a **regular 3D network** whereby the positive ions are surrounded by negative ions and the negative ions are surrounded by positive ions. The attractive forces between ions of opposite charge are classified as electrostatic forces (forces between particles of opposite charge) and are known as **ionic bonds**. The structure is often referred to as network, because there is no fixed number of ions in the structures, they have an infinite structure. The diagram shows the structure of sodium chloride, NaCl.  The formula, NaCl, refers to the combining ratio of Na^+^ and Cl^--^ ions. NB: This structure cannot be classified as a molecule, because the number of ions of each type is not fixed. Remember, a molecule has a finite number of atoms of each element. Properties of ionic compounds -------------------------------------------------------------------------------------------------------- **EXPLAIN** the properties of ionic compounds, including melting point, conductivity and malleability. -------------------------------------------------------------------------------------------------------- Ionic compounds are: - Solids at room temperature -- they all have high melting points. - Brittle -- they are broken easily when an external force is applied. - Electrically conductive when molten (liquid) or dissolved in water. - Mostly soluble in water. *Why do ionic compounds have high melting points?* *For a substance to melt, attractive forces between the particles that make up the substance must be overcome.* ***The electrostatic forces between opposite charged ions is very strong**. A lot of energy is required to overcome these strong attractive forces and therefore ionic compounds melt at high temperatures.* A diagram of a molecule Description automatically generated with medium confidence *Why are ionic compounds brittle?* When an external force is applied to the ionic crystal, ions of the same charge are pushed closer and closer together. Like charges repel and the layers within the ionic lattice move away from each other and the lattice fractures.  *Why do ionic compounds conduct electricity in liquid and aqueous states?* When molten or dissolved in water, ions are free to move and transfer charge. Ionic Bonding - Chemistry Demonstration -- conductivity of ionic compounds ================================================ ---------------------------------------------------------------------------------------------------------- **OBSERVE** a demo (or video demo) of the conductivity of an ionic substance when solid and when molten. ---------------------------------------------------------------------------------------------------------- Solubility of ionic compounds ============================= ---------------------------------------------------------------------------- **USE** the solubility rules to predict the solubility of ionic compounds. ---------------------------------------------------------------------------- Many ionic compounds dissolve in water, for example sodium chloride. Sodium chloride dissolves in water, because the sodium and chloride ions are stabilised by water molecules.  ========================================================================= Solubility rules enable chemists to determine which ionic compounds are soluble. ================================================================================ Solubility rules are as follows: ================================ 1. 2. 3. 4. 5. 6. Activity: Which ionic compounds dissolve in water? ================================================== Write down the formula of the salt produced by each positive and negative ion and deduce whether the ionic compound produced will dissolve in water. ==================================================================================================================================================== Cl^--^ Br^--^ I^--^ OH^--^ NO~3~^--^ CH~3~COO^--^ CO~3~^2--^ ---------- -------- -------- ------- -------- ----------- -------------- ------------ Li^+^ Na^+^ K^+^ Mg^2+^ Ca^2+^ Ba^2+^ Ag^+^ Pb^2+^ NH~4~^+^ Covalent molecular compounds ============================ +-----------------------------------------------------------------------+ | **DEFINE** a **molecule** as a finite structure with given number of | | non-metal atoms of specific elements and give examples of molecules o | | f both simple covalent compounds and gaseous elements. {#define-a-mol | | ecule-as-a-finite-structure-with-given-number-of-non-metal-atoms-of-s | | pecific-elements-and-give-examples-of-molecules-of-both-simple-covale | | nt-compounds-and-gaseous-elements..BodyText} | | ===================================================================== | | ===================================================================== | | ====================================================== | +=======================================================================+ | **DEFINE** a *covalent bond* as a shared pair of electrons between tw | | o atoms. {#define-a-covalent-bond-as-a-shared-pair-of-electrons-betwe | | en-two-atoms..BodyText} | | ===================================================================== | | ======== | +-----------------------------------------------------------------------+ | **APPRECIATE** that *covalent bonding* involves the electrostatic att | | raction between the shared pair of electrons and the nucleus of each | | atom. {#appreciate-that-covalent-bonding-involves-the-electrostatic-a | | ttraction-between-the-shared-pair-of-electrons-and-the-nucleus-of-eac | | h-atom..BodyText} | | ===================================================================== | | ===================================================================== | | ===== | +-----------------------------------------------------------------------+ {#section-285.BodyText} Compounds that are made up of neutral atoms rather than ions are known as covalent compounds. Covalent compounds are made from non-metal atoms only. {#compounds-that-are-made-up-of-neutral-atoms-rather-than-ions-are-known-as-covalent-compounds.-covalent-compounds-are-made-from-non-metal-atoms-only..BodyText} ==================================================================================================================================================== {#section-286.BodyText} Recall that **ionic compounds** are made up of **ions** held together by **ionic bonds**. {#recall-that-ionic-compounds-are-made-up-of-ions-held-together-by-ionic-bonds..BodyText} ========================================================================================= {#section-287.BodyText} **Covalent molecular compounds** are made up of **neutral atoms** held together by **covalent** **bonds**. {#covalent-molecular-compounds-are-made-up-of-neutral-atoms-held-together-by-covalent-bonds..BodyText} ========================================================================================================== {#section-288.BodyText} Most, (but not all), covalent compounds exist as molecules. Molecules are stable particles. {#most-but-not-all-covalent-compounds-exist-as-molecules.-molecules-are-stable-particles..BodyText} =========================================================================================== {#section-289.BodyText} A molecule is a **finite** structure with a **fixed number of atoms of specific elements**. This is very different from the infinite structure of lattices such as those found in ionic solids. {#a-molecule-is-a-finite-structure-with-a-fixed-number-of-atoms-of-specific-elements.-this-is-very-different-from-the-infinite-structure-of-lattices-such-as-those-found-in-ionic-solids..BodyText} =============================================================================================================================================================================================== {#section-290.BodyText} Here are some examples of common molecules: {#here-are-some-examples-of-common-molecules.BodyText} =========================================== {#section-291.BodyText} +-----------------------------------+-----------------------------------+ | *Compound name* {#compound-name-2 | *Formula* {#formula.BodyText} | |.BodyText} | ========= | | =============== | | +===================================+===================================+ | Water {#water.BodyText} | H~2~O {#h2o.BodyText} | | ===== | ===== | | | | | h2o 3d model | | | ============ | | +-----------------------------------+-----------------------------------+ | Ammonia {#ammonia.BodyText} | NH~3~ {#nh3.BodyText} | | ======= | ===== | | | | | {#section-292.BodyText} | | | | | |  {#ammoni | | | a---american-chemical-society.Bo | | | dyText} | | | ================================= | | | ======================== | | +-----------------------------------+-----------------------------------+ | Methane {#methane.BodyText} | CH~4~ {#ch4.BodyText} | | ======= | ===== | | | | | Famous Molecules - Methane Molecu | | | le, HD Png Download , Transparent | | | Png Image - PNGitem {#famous-mol | | | ecules---methane-molecule-hd-png- | | | download-transparent-png-image--- | | | pngitem.BodyText} | | | ================================= | | | ================================= | | | ==================== | | +-----------------------------------+-----------------------------------+ Recap: naming covalent molecular compounds When naming molecular compounds, the first element name is not changed and the second has its final syllable replaced with 'ide'. Generally these compounds have names which tell you the formula, for example: carbon monoxide CO(g) carbon dioxide CO~2~(g) When deciding which element to write first in the name, just remember that the element furthermost to the left or closer to the bottom in the Periodic Table goes **first**, e.g. PCl~3~ is phosphorus trichloride **not** trichloride phosphorus. The exception is oxygen, which almost always is written second in the name, e.g. chlorine oxide not oxygen chloride. The prefixes used in chemical names are shown in the table below. **Prefix** ------------ --- Mono- 1 di- 2 Tri- 3 Tetra- 4 Penta- 5 Hexa- 6 Note that some compounds have common names such as water, H~2~O, ammonia, NH~3~, and methane, CH~4~. In such cases, the common name should be used. Activity: Name the following: -------------------------- ------------- **Name** **Formula** dinitrogen monoxide N~2~O~(g)~ NO~(g)~ N~2~O~3(g)~ NO~2(g)~ dinitrogen pentaoxide dinitrogen tetraoxide carbon tetrachloride BF~3(g)~ SF~6(g)~ phosphorus pentachloride P~2~O~5(s)~ -------------------------- ------------- Lewis electron dot diagrams =========================== {#section-294.BodyText} +-----------------------------------------------------------------------+ | **DRAW** Lewis dot diagrams (outer shell electrons only) of common co | | valent compounds. {#draw-lewis-dot-diagrams-outer-shell-electrons-onl | | y-of-common-covalent-compounds..BodyText} | | ===================================================================== | | ================= | +-----------------------------------------------------------------------+ {#section-295.BodyText} The number of valence (outer) electrons an atom has will determine how the atom forms covalent bonds with other atoms. {#the-number-of-valence-outer-electrons-an-atom-has-will-determine-how-the-atom-forms-covalent-bonds-with-other-atoms..BodyText} ====================================================================================================================== Lewis electron dot diagrams are used to represent atoms in terms of atomic symbol and number of valence electrons. {#lewis-electron-dot-diagrams-are-used-to-represent-atoms-in-terms-of-atomic-symbol-and-number-of-valence-electrons..BodyText} ================================================================================================================== {#section-296.BodyText} For example: {#for-example-1.BodyText} ============ *Atom* *Lewis dot structure* --------------- ----------------------- Hydrogen atom Carbon atom Nitrogen atom Oxygen atom When an atom forms a covalent bond with another atom, valence electrons are shared. The octet rule is always obeyed (for now...). For example: When two hydrogen atoms form a hydrogen molecule, the two electrons are shared across both atoms such that both atoms have full valence shells. The electron pair is attracted to both nuclei. The result is a strong covalent bond between the two hydrogen atoms. When two oxygen atoms form an oxygen molecule, the 12 electrons are shared across both atoms such that both atoms have full valence shells. The result is a strong (double) covalent bond between the two oxygen atoms. Drawing Lewis dot diagrams -- single bonds ========================================== {#section-297.BodyText} **Complete the table to help you work out the relationship between electron structure and** number of covalent bonds an atom can form. *Element* *Number of valence electrons* *Number of additional electrons required to fill valence shell* *Maximum number of covalent bonds it can form* ------------ ------------------------------- ----------------------------------------------------------------- ------------------------------------------------ Hydrogen 1 1 1 Helium Nitrogen Oxygen Phosphorus Sulphur Carbon Follow the guidelines below, using water as an example, when drawing Lewis dot diagrams. 1 Draw Lewis dot diagrams for each atom in the molecule. --- ---------------------------------------------------------------------------------------------------------------------- -- 2 Calculate the total number of valence electrons. 3 Work out which atom can form the greatest number of covalent bonds and put this atom in the middle of your molecule. 4 Share out the electrons so that each atom has a full valence shell of electrons. 5 Draw one line for each pair of electrons that is shared. Activity: Drawing Lewis dot diagrams ==================================== a. Chlorine, Cl~2~ b. Hydrogen chloride, HCl c. Carbon tetrachloride, CCl~4~ d. Methane, CH~4~ Drawing Lewis dot diagrams -- Double and triple bonds ===================================================== We will follow the same guidelines as before, using carbon dioxide as an example. 1 Draw Lewis dot diagrams for each atom in the molecule. --- ---------------------------------------------------------------------------------------------------------------------- -- 2 Calculate the total number of valence electrons. 3 Work out which atom can form the greatest number of covalent bonds and put this atom in the middle of your molecule. 4 Share out the electrons so that each atom has a full valence shell of electrons. 5 Draw one line for each pair of electrons that is shared. Practice in the space below by drawing nitrogen, N~2~: Activity: Drawing Lewis dot diagrams ==================================== {#section-298.BodyText} {#section-299.BodyText} +-----------------------+-----------------------+-----------------------+ | *Compound* {#compound | *Formula* {#formula-1 | *Lewis dot diagram* { | |.BodyText} |.BodyText} | #lewis-dot-diagram.B | | ========== | ========= | odyText} | | | | =================== | +=======================+=======================+=======================+ | Fluorine {#fluorine-1 | {#section-300.BodyT | {#section-301.BodyT | |.BodyText} | ext} | ext} | | ======== | | | +-----------------------+-----------------------+-----------------------+ | Hydrogen bromide {#hy | {#section-302.BodyT | {#section-303.BodyT | | drogen-bromide.BodyT | ext} | ext} | | ext} | | | | ================ | | | +-----------------------+-----------------------+-----------------------+ | {#section-304.BodyT | NH~3~ (g) {#nh3-g.Bo | {#section-305.BodyT | | ext} | dyText} | ext} | | | ========= | | +-----------------------+-----------------------+-----------------------+ | {#section-306.BodyT | CCl~4~ (g) {#ccl4-g. | {#section-307.BodyT | | ext} | BodyText} | ext} | | | ========== | | +-----------------------+-----------------------+-----------------------+ | Carbon dioxide {#carb | {#section-308.BodyT | {#section-309.BodyT | | on-dioxide.BodyText} | ext} | ext} | | ============== | | | +-----------------------+-----------------------+-----------------------+ | Nitrogen trichloride | {#section-310.BodyT | {#section-311.BodyT | | {#nitrogen-trichlorid | ext} | ext} | | e.BodyText} | | | | ==================== | | | +-----------------------+-----------------------+-----------------------+ Activity: More Lewis dot diagrams ================================= {#section-312.BodyText} +-----------------------+-----------------------+-----------------------+ | *Compound* {#compound | *Formula* {#formula-2 | *Lewis dot diagram* { | | -1.BodyText} |.BodyText} | #lewis-dot-diagram-1 | | ========== | ========= |.BodyText} | | | | =================== | +=======================+=======================+=======================+ | ethane {#ethane.Body | C~2~H~6~ {#c2h6.Body | {#section-