IB Past Paper: Atomic Model Theories PDF

Topic 1.1 The nuclear atom Basic Experimental Sciences  1.1 Outline the theories of the atomic model in a timeline. Background to the atomic theory ⚛ 440 BCE, Democritus ⚛ Matter is composed of indivisible particles termed atomos. ⚛ In Greek, the word "atom" means...

Topic 1.1 The nuclear atom Basic Experimental Sciences  1.1 Outline the theories of the atomic model in a timeline. Background to the atomic theory ⚛ 440 BCE, Democritus ⚛ Matter is composed of indivisible particles termed atomos. ⚛ In Greek, the word "atom" means "indivisible". Democritus's Atomic Model. [Image]. Democritus. [Image]. Retrieved on Aug. 23, 2015 from: Retrieved on Aug. 23, 2015 https://the-history-of-the-atom.wikispa from: ces.com/Democritus http://www.nndb.com/peopl e/790/000087529/  – France, 1782: Lavoisier – The law of conservation of mass: “Mass cannot be created or destroyed, it is merely rearranged”. – France 1799: Joseph Proust – Law of definite proportions: “A chemical compound always contains exactly the same proportion of elements by mass.” Retrieved from: https://upload.wikimedia.org/wikipedia/commons/th umb/a/a5/Marcel_Proust_1900-2.jpg/200px-Marcel _Proust_1900-2.jpg  England 1803, John Dalton ⚛ Dalton’s atomic theory: 1. Matter is composed of extremely small particles called atoms. [Image]. Retrieved on Aug. 16, 2. An element consists of atoms of the 2015 from: http://www.bbc.co.uk/schools/ gcsebitesize/science/aqa_pre same type only. _2011/rocks/atomsrev1.shtml 3. Different atoms combine in simple whole-number ratios to form compounds. 4. In a chemical reaction, atoms are separated, combined or rearranged, but never destroyed. [Image]. Retrieved on Aug. 16, 2015 from: http://thehistoryoftheatom.wee bly.com/john-dalton.html  Joseph Thompson. – England 1897, Joseph Thomson [Photograph]. Retrieved from: http://global.brit annica.com/bio graphy/J-J-Tho – Identifies the electron. mson – The electron has a negative charge. [Image]. Retrieved on Aug. 16, 2015 from: http://nathali256.bl ogspot.mx/2010/10 – Plum-pudding model. /evolution-and-hist ory-of-atomic-mod el.html Ernest Rutherford. – New Zealand, 1909, Ernest Rutherford [Photograph]. Retrieved from: http://www.nobelp rize.org/nobel_priz – Discovered the atomic nucleus, and es/chemistry/laure ates/1908/rutherfo rd-bio.html proton, with its positive charge. – Experimented on a thin gold foil. Concluded that an atom consists of a nucleus and empty space through which the electrons move. [Image]. Retrieved on Aug. 16, 2015 from: http://linoit.com/users/bjhnd1/canvases/Atomic%20Model%20Scientist  Denmark 1913, Niels Bohr Niels Bohr. – Published a theory of atomic structure relating the [Photograph]. Recuperda de: arrangement of the electrons in the atom in fixed http://www.no belprize.org/n obel_prizes/p orbits around the core, just as the planets move in hysics/laureat es/1922/bohr- photo.html orbits around the sun. – He assigned a quantum number (energy level) to each orbit. [Imagen]. Recuperda de: Austria 1926, Erwin Schrödinger http://www.fromquarkstoquasars.com/know-your -scientist-niels-bohr-the-father-of-the-atom/ Erwin – Quantum mechanical model: Electrons occupy Schrödin ger. [Photogra only certain orbitals around the nucleus. Those ph]. Retrieved orbitals are stable and are called "stationary" from: http://facu lty.wcas.n orbitals. orthweste rn.edu/~in focom/Ide as/quantu – Calculated energy sublevels and orbitals. Each m_timelin e.html orbital has an energy associated. – Introduce the electron cloud model.  [Image]. Retrieved from: https://scie nceconcepti ons.wikispa ces.com/Or – Germany 1927, Werner Heisenberg biting+Elect rons – The uncertainty principle: “States that we Heisenberg, Werner. cannot know both the position and trajectory [Photograph]. In Britannica Online for Kids. of an electron, with perfect accuracy; the Retrieved from: http://kids.britann ica.com/compton more we nail down the electron’s position, s/art-144936 the less we know about its trajectory and vice James Chadwick. versa.” [Photograph] Retrieved on Aug. 16, 2015 from: https://reich-c – England 1932, James Chadwick hemistry.wiki spaces.com/ M.Schmidt+T ime+Line+Pr – Proves the existence of neutrons. oject – Determines that the atomic number is determined by the number of protons in the nucleus of the atom. Electron Cloud Model. [Image]. Retrieved from: https://bfrohwein.wikispaces.com/Electron+Cloud+Model  1.2 Identify the subatomic particles (proton, neutron and electron). ⚛ Atom: ⚛ Smallest particle of an element that retains the properties of the element. [Image]. Retrieved on 16 de ago. 2015 from: http://www.projectsharetexas.org/resource/matter-and-energy-atomic-structure  1.2 Identify the subatomic particles (proton, neutron and electron). ⚛ Atom: ⚛ Atoms of an element are different from the atoms of another element. ⚛ Atoms have subatomic particles: protons, neutrons and electrons. ⚛ At the nucleus of each atom are protons and neutrons , which contain the positive charge and the total mass of the element. ⚛ The nucleus occupies a very small part of the center of an atom. ⚛ Most atom includes an empty space around the nucleus, through which electrons move. ⚛ The electrons of an atom move around the nucleus in defined regions called orbits.  1.2 Identify the subatomic particles (proton, neutron, and electron). Subatomic particles: ⚛ Proton (p+): has positive charge. ⚛ Electron (e-): Has a negative charge and its mass is extremely small. it moves around the nucleus in defined spaces called orbitals. ⚛ Neutron (n°): Subatomic particle which Retrieved from https://cdn.sparkfun.com/assets/0/4/e/8/2/519fa09dce395f8b08000000.png has no electric charge (it is neutral). Nearly equal to the mass of a proton.  1.2 Identify the subatomic particles (proton, neutron, and electron). Table 1. Subatomic particles properties. Relative Relative Particle Symbol Location electric charge mass Around the Electron e- - 1/1840 nucleus Proton P+ At the nucleus + 1 Neutron n° At the nucleus 0 1  1.2 Identify the subatomic particles (proton, neutron, and electron). How atoms differ. Atoms of an element are different from the atoms of another element. ⚛ The number of protons in an atom is unique and identifies it. This number is the atomic number of the atom. ⚛ The mass number of an atom is equal to its total number of protons and neutrons. Atomic Number Atomic Mass Image retrieved from: https://es.123rf.com/photo_62995132_carbono-elemento-quimico-el-grafito-y-el-diamante-icono-de-color-con-el-numero-atomico-y-el-peso-ato.htmlI  1.2 Identify the subatomic particles (proton, neutron, and electron). Atoms of the same element with different numbers of neutrons and different masses are called isotopes. The atomic weight of an element is a weighted average of the masses of all isotopes of that element found in nature. Image Retrieved from: http://ciencianxt.blogspot.mx/2015/04/datacion-mediante-el-carbono-14.html  1.2 Identify the subatomic particles (proton, neutron, and electron). Conclusions about Atoms… Atoms are electrically neutral, because they have equal numbers of protons and electrons, they have no electric charge. Ions* electrons (-) protons (+) Image retrieved from: https://qisomamedicina.blogspot.com/2012/10/como-favorecen-la-salud-los-iones_29.html  1.2 Identify the subatomic particles (proton, neutron, and electron). continue Conclusions… The nucleus of each atom holds protons and neutrons, so it contains the total mass of the atom. The nucleus occupies a very small part at the center of an atom. Most of an atom is an empty space around the nucleus, through which electrons move. Image: https://www.thoughtco.com/atomic-weight-and-atomic-mass-difference-4046144 Topic 1.3 Periodic Table [Image]. Retrieved from: http://i.livescience.com/images/i/000/034/144/original/periodic-table-elements-121206c.jpg?1354814553  1.3.1 Identify the location of the atomic mass and atomic number in the elements of the periodic table. ⚛ Each box of the periodic table belongs to an element, and the numbers that appear make reference to the characteristics of the atoms of that element. ⚛ Atomic number: a number that corresponds to the number of protons of the element. ⚛ Atomic mass: the weighted average mass of all the naturally occurring isotopes of an element. Rounded to a whole number it corresponds to the sum of protons and neutrons in the nucleus. [Image]. Retrieved from: http://chemwiki.ucdavis.edu/@api/deki/files/8320/He_Atom.png?size=bestfit&width=200&height=165&revision=1 1.3.1 Identify the location of the atomic mass and atomic number in the elements of the periodic table. Mass Number Sum of protons and neutrons in an atom [Image]. Retrieved from: http://infowiring.today/atomic-number-explain-with-diagram.html  1.4.1 State that the principal energy level is a whole number, n. Electron Configuration It is the representation of the arrangement of electrons distributed among the orbital shells in an atom. Remember that atoms are composed of subatomic particles as follows: Protons (+) Neutrons (0) } nucleus Electrons (-) } e- cloud [Image]. Retrieved on June 2, 2015 from: http://chemistry.tutorcircle.com/inorganic-chemistry/subatomic-parti cles.html  Energy Levels Electrons are located in different energy levels and sublevels in the electron cloud, surrounding the nucleus of the atom. Energy levels are named using numbers 1 to 7, or the letters K to Q. Each level or shell has a maximum number of e-. Phillips, Strozak, Wistrom, Chemistry (2011). USA: Pearson. [Image]. Retrieved on June 2, 2015 from http://slideplayer.com/slide/276496/  1.4.2 State that a more detailed atomic model describes the division of the principal energy level into sublevels s, p, d and f with higher energies. Sublevels / Subshells ⚛ Each energy level contains one or more sublevels: s, p, d, and f. ⚛ The maximum number of e- each sublevel can hold is: s = 2; p = 6; d = 10; f = 14. ⚛ Each sublevel or subshell is divided into orbitals, which are 3-D regions of space where a pair of e- is more likely to be found. [Image]. Retrieved on June 2, 2015 from: http://chemistry11mrstandring.wikispaces.com/LIine+spectra,+electron+shells+and+energy+level+diagrams  1.4.3 State that sublevels contain a fixed number of orbitals, regions of space where an electron is more likely to be found. Orbitals ⚛ Since each orbital can hold 2e-, the number of orbitals and electrons each sublevel can hold is: Sublevel Orbitals # of Electrons s 1 x 2e- = 2 p 3 x 2e- = 6 d 5 x 2e- = 10 f 7 x 2e- = 14  Energy Levels and Sublevels Energy level Sublevels Maximum Orbitals number of e- 1 s 2 s2 2 s, p 8 s2 , p 6 3 s, p, d 18 s2, p6, d10 4 s, p, d, f 32 s2, p6, d10, f14 5 s, p, d, f 32 s2, p6, d10, f14 6 s, p, d 18 s2, p6, d10 7 s, p 8 s2 , p 6  Electron Configuration * Displays the # of e- in each E level and sublevel. For Hydrogen ( Z = 1 ): # of electrons 1 Energy level 1s Sublevel How many e- does Helium have? Use the periodic table to find out. Hint: atomic # = # protons…  1.2.4 State that each orbital has a determined energy level and is capable of holding two electrons with opposite spin. The electron configuration for He (Z = 2) is: 1s2 Its electron distribution/orbitals diagram ↑↓ is: 1s Lithium (Z = 3): 1s2, 2s1 ↑↓ ↑ 1s 2s Boron (Z = 5): 1s2, 2s2, 2p1 ↑↓ ↑↓ ↑ Note: the orbitals must be written, even if they are not filled. 1s 2s 2p 2p 2p  Practice 1 Write the electron configuration and electron distribution/orbitals diagram for Ne and Al. 2 2 6 ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ Ne (Z=10): 1s , 2s , 2p 1s 2s 2p 2p 2p Al (Z=13): 1s2, 2s2, 2p6, 3s2, 3p1 ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑ 1s 2s 2p 2p 2p 3s 3p 3p 3p  Predicting Groups and Periods ⚛ An element's Group in the Periodic Table is determined by the number of valence electrons in the last level. ⚛ An element's Period in the Periodic Table is determined by the number of the highest energy level. ⚛ Example: Cl (Z = 17) 1s2 2s2 2p6 3s2 3p5 ⚛ Group 17 / VIIA Period 3  Blocks ⚛ Sets of elements that show the electron configuration, sublevels and orbitals occupied by valence e- of atoms in the periodic table. [Imege]. Retrieved on June 2, 2015 from: http://ehschemcorner.blogspot.mx/2011/09/atom-periodic-table-electron.html  Electron Arrangement in Atoms ⚛ Aufbau Principle: electrons will occupy the lowest energy level possible, and “build up” to higher energy levels. ⚛ Pauli Exclusion Principle: No two electrons can share the same [Image]. Retrieved on June 2, 2015 from: https://www.studyblue.com/notes/ combination of the four quantum note/n/electron-configuration-and-t he-periodic-table/deck/965466 numbers. Since only 2 electrons may occupy an orbital, they must have opposite spin (clockwise & counterclockwise). [Image]. Retrieved on June 2, 2015 from: http://chemwiki.ucdavis.edu/Inorganic_Chemistry/Electronic_Confi gurations/Pauli_Exclusion_Principle  Electron Arrangement in Atoms Hund's Rules: when filling a sublevel, such as 3p, e- will go to an empty orbital prior to pairing up (spread out before pairing up). Serge Veretennikov (UCD Spring 2011) [Image]. Retrieved on June 3, 2015 from: http://chemwiki.ucdavis.edu/Inorganic_Chemistry/Electronic_Configurations/Hund%27s_Rules  Practice 2 Write the electron configuration of the Noble Gases: He, Ne, Ar, Kr. Find their number of e- in the periodic table. He (Z=2): 1s2 Ne (Z=10): 1s2, 2s2, 2p6 Ar (Z=18): 1s2, 2s2, 2p6, 3s2, 3p6 Kr (Z=36): 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6  Abbreviated electron configuration Uses the electron configuration of the Noble Gases to substitute part of that of atoms with a higher atomic number. Element symbol in brackets: [He]= 1s2 Phillips, John, Strozak, Victor, Wistrom, Cheryl. (1997).[Image]. Retrieved on June 4, 2015 from: http://slideplayer.com/slide/276496/  Practice 3 Write the standard and abbreviated / shorthand electron configuration of B, Al, Ge Standard Abbreviated B5 : 1s2, 2s2, 2p1 [He2] 2s2, 2p1 Al 13 : 1s2, 2s2, 2p6, 3s2, 3p1 [Ne10] 3s2, 3p1 Ge 32: 1s2,2s2,2p6,3s2,3p6, 4s2, 3d10, 4p2 [Ar18] 4s2, 3d10, 4p2 Quantum Numbers  Quantum Numbers Name Symbol Description Values Principal n Orbital energy Positive integers (1, 2, 3, 4…) Angular l Orbital shape Integers from Momentum 0 to n-1… Magnetic m Orientation Integers from - l to 0 to + l Spin s Electron spin +1/2 or -1/2 [Image] Retrieved on September 1st, 2015, from: http://crescentok.com/staff/jaskew/isr/chemistry/quantum.htm  Principal Quantum Number n Describes the energy level in the atom (1 through 7). The maximum number of electrons in n is 2n2. [Image] Retrieved on September 1st, 2015, from: http://www.learner.org/interactives/periodic/elementary2.html  Angular (subshell) Quantum Number l ⚛ Describes the sublevel within n. ⚛ Possible values are 0 to n-1 (formula). ⚛ Describes the shape of a given orbital [Image] Retrieved on September 1st, 2015, from: http://hdimagelib.com/azimuthal+quantum+numbers  Magnetic Quantum Number m Describes the orbital within l. Values range between -l to 0 to +l, where “l” is the Angular quantum number” s (l=0) has 1 orbital p (l=1) has 3 orbitals d (l=2) has 5 orbitals f (l=3) has 7 orbitals [Image] Retrieved on September 1st, 2015, from: http://chemwiki.ucdavis.edu/Physical_Chemistry/Quantum_Mechanics/09._The_Hydrogen_Atom/Atomic_Theory/Electrons_in_Atoms/Electronic_Orbitals  Spin Quantum Number s ⚛ Describes the spin of the electrons in an orbital. ⚛ Electrons in the same orbital must have opposite spins. ⚛ Possible spins are clockwise or counterclockwise. [Image] Retrieved on September 1st, 2015, from: http://images.slideplayer.com/1/268246/slides/slide_7.jpg  1.5.1 Predict the positive ions (cations) that form as metals lose valence electrons. 1.5.2 Predict the negative ions (anions) that form as nonmetals gain electrons. Electrons experience a force of Key terms attraction from both nucleus. This negative-positive-negative attraction holds the two particles together. ⚛ Chemical bond: The attractive forces that hold atoms together in molecules or formula units. This attraction is called a chemical bond. A pair of electrons form a bond. [Image]. Retrieved from: http://www.wonderwhizkids.com/index.php/biology/biochemistry/ch emical-bonding  1.5.1 Predict the positive ions (cations) that form as metals lose valence electrons. 1.5.2 Predict the negative ions (anions) that form as nonmetals gain electrons. ⚛ Ion.- An atom or group of atoms that has either lost or gained electrons. [Image]. Retrieved from: http://www.chemicool.com/the-periodic-table.html [Image]. Retrieved from: http://www.wonderwhizkids.com/index.php/biology/biochemistry/ch emical-bonding  1.5.1 Predict that positive ions (cations) are formed when metals lose valence electrons 1.5.2 Predict that negative ions are formed when metals gain electrons Some atoms tend to give up/lose their electrons: METALS (low Electronegativity) Others tend to receive/gain electrons: NONMETALS (high Electronegativity) [Image]. Retrieved from: http://web.sbu.edu/chemistry/wier/atoms/ions.html  1.5.1 Predict that positive ions (cations) are formed when metals lose valence electrons 1.5.2 Predict that negative ions (anions) are formed when metals gain electrons. Types of chemical bonds 1. Ionic bonds – Are the attraction forces between opposite ions. – Involve the transfer of electrons. – 2. Covalent bonds – Involve sharing electrons. [Image]. Retrieved from: http://kitkatyj.deviantart.com/art/The-four-chemical-bonds-395098750  1.5.1 Predict that positive ions (cations) are formed when metals lose valence electrons 1.5.2 Predict that negative ions (anions)are formed when metals gain electrons Attraction force between opposite ions is called IONIC BOND. Ionic bond in NaCl [Imagen] Recuperada el 28de Julio de 2017 de: http://macrotomicro.blogspot.com/2011/02/ionic-bond-in-nacl.html  What is an ion? An ion is a charged atom or molecule. It is changed because the number of electrons do not equal the number of proton in the atom or molecule. An atom can acquire a positive charge or a negative charge depending on whether the number of electrons in an atom is greater or less then the number of protons in the atom. A Recuperado el 14 junio 2022 de: https://i.gifer.com/OFI1.gif  1.5.1 Predict the positive ions (cations) forming as metals lose valence electrons. 1.5.2 Predict the negative ions (anions) forming as non- metals gain electrons. CATION Is an ion that has lost one or more electrons, giving a net positive charge, formed when metals lose valence electrons. Ex: K+, NH4+1 [Image]: Retrieved from: http://www.gcsescience.com/a4-sodium-ion.htm ANION Is an ion that has gain one or more electrons, giving a net negative charge, formed when nonmetals gain electrons. Ex: S-2, SO4-2 [Image]: Retrieved from: http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/bonding/ioni c_bondingrev3.shtml.51.1 Predict the positive ions (cations) forming as metals lose valence electrons. 1.5.2 Predict the negative ions (anions) forming as non- metals gain electrons. Ions can be: + - a) Monoatomic: a single element with charge. Ex: Na+1, Cl- b) Polyatomic: group of elements (cluster of two or more) having an overall charge. Ex: SO4-2, NH4+1. [Image]. Retrieved from:http://contest.japias.jp/tqj14/140054/egensi.html  1.5.3 Compare and contrast the ionic and covalent bonds Covalent bonds ⚛ Are formed by the sharing of electrons. ⚛ Notice that these atoms DO NOT form ions. The attraction between them is purely by sharing electrons. ⚛ A molecule is formed when [Image]. Retrieved on Sept. 11, 2015 from: two or more atoms bond http://www.gcsescience.com/a30-covalent-bond-w ater-molecule.htm covalently.  1.5.3 Compare and contrast ionic and covalent bonds. Covalent bonds ⚛ Carbon has 4 valence electrons, so it is missing 4 e- to complete an octet. ⚛ Being a nonmetal, C tends to share these 4 electrons. ⚛ On the other hand, hydrogen has only 1 valence electron. It needs another one to be stable. [Image]. Retrieved from: http://blog.vadaenergy.com/?p=554 ⚛ So, C and H can share their electrons. That way they are all stable atoms.  1.5.3 Compare and contrast ionic and covalent bonds Compare ionic and covalent bonds: Ionic bonds Covalent bonds 1. Both of them are types of bonds between elements. 2. Both of them allow the formation of chemical compounds. 3. Both of them want to obtain 8 valence electrons in order to complete their octet rule.  1.5.3 Compare and contrast ionic and covalent bonds Contrasting ionic and covalent compounds. Ionic compounds Covalent compounds Transfer of electrons Sharing electrons Metal + Nonmetal Nonmetal + nonmetal High mp/bp Molecular (low mp/bp) Solid at room T Liquid or gaseous at room T Example: NaCl Example: CO2, Cl2 Conduct electricity. Non conductors of electricity.