Chem 1004 Monday Recitation PDF

Chem 1004 Monday Recitation Jeffry Guerrero, CUNY Hunter College PAGE 1  Updates Lewis Dot Structure & Naming Binary Todays Inorganic Compounds Agenda Discussion/Questions PAG...

Chem 1004 Monday Recitation Jeffry Guerrero, CUNY Hunter College PAGE 1  Updates Lewis Dot Structure & Naming Binary Todays Inorganic Compounds Agenda Discussion/Questions PAGE 2 Updates § This lab will be online § The recitation will be about Lewis Dot structures § The lab will cover the second half of these slides regarding ionic and covalent naming Updates PAGE 3 Focus Questions/Discussion Focus § Lewis Dot § Naming Binary Covalent Compounds § Naming Binary Ionic Compounds § Ionic compounds with Polyatomic or Complex ions Focus PAGE 4 Updates Questions/Discussions Lewis Dot Structure § Electrons orbit around a nucleus and at different ”shells” § Electrons in the outermost shell are called valence electrons § Valence electrons determine a atoms behavior and bonding Focus PAGE 5 Updates Questions/Discussions Lewis Dot Structure § We can see bonding and lone pairs of electrons with the Lewis Dot Structure § This is for small molecules and molecules with a central atom Focus PAGE 6 Updates Questions/Discussions Lewis Dot Structure § Examples Focus PAGE 7 Updates Questions/Discussions Lewis Dot Structure § Carbon has 4 electrons and hydrogen has 1, why? Focus PAGE 8 Updates Questions/Discussions How to draw a Lewis Dot Structure § 1) Find the total number of valence electron § valence electrons are equal to the atom's main group number. Focus PAGE 9 Updates Questions/Discussions How to draw a Lewis Dot Structure § 1) Find the total number of valence electron § Add an electron for every positive charge and subtract for positive. Focus PAGE 10 Updates Questions/Discussions How to draw a Lewis Dot Structure § 1) How many valence electrons does Hydrogen have? Lithium? Beryllium? Boron? Carbon? Nitrogen? Oxygen? Fluorine? Focus PAGE 11 Updates Questions/Discussions How to draw a Lewis Dot Structure § 1) How many valence electrons do these have? Focus PAGE 12 Updates Questions/Discussions How to draw a Lewis Dot Structure § 2) The central atom is the least electronegative Focus PAGE 13 Updates Questions/Discussions How to draw a Lewis Dot Structure § 2) The central atom is the least electronegative § This is the trend for electronegative atoms Focus PAGE 14 Updates Questions/Discussions  How to draw a Lewis Dot Structure § 2) The central atom is the least electronegative (except H) § Remember the octet rule, row 1 has a maximum of 2 electrons § Row 2 has a maximum of 8 electrons § Row 3 and on have >8 because of orbitals Focus PAGE 15 Updates Questions/Discussions How to draw a Lewis Dot Structure § 3) Assign leftover electrons to terminal atoms, subtract electrons from total in step 2 Focus PAGE 16 Updates Questions/Discussions How to draw a Lewis Dot Structure § 3) Draw 𝐶𝐻! 𝑂 Focus PAGE 17 Updates Questions/Discussions How to draw a Lewis Dot Structure § 4) If the central atom doesn’t have a full octet, make multiple bonds 𝐶𝐻! 𝑂 Focus PAGE 18 Updates Questions/Discussions Summary § 1) Find the total number of valence electron § 2) The central atom is the least electronegative § 3) Assign leftover electrons to terminal atoms, subtract electrons from total in step 2 § 4) If the central atom doesn’t have a full octet, make multiple bonds Focus PAGE 19 Updates Questions/Discussions Ionic vs Covalent § Bonding is the sharing of electrons, due to valence electrons and to complete octet § Ionic bonding is when there is a transfer of electrons from a metal to a non-metal to obtain a full valence shell for both atoms. Focus PAGE 20 Updates Questions/Discussions Ionic vs Covalent § A covalent bond is when two different atoms come together to share electrons Focus PAGE 21 Updates Questions/Discussions  Ionic vs Covalent Ionic Covalent Focus PAGE 22 Updates Questions/Discussions Ionic vs Covalent § Officially the easiest way to see if a bond is ionic or nonpolar/polar (let's consider these covalent) is by taking their difference in electronegativity § Remember the trend in electronegativity? § But an easy way to find out if it’s ionic or covalent is it see where the atoms are on a periodic table. § Ionic bonds generally form between metals (left side of PT) and nonmetals (right side of PT) § So covalent bonds are generally between atoms on the right Focus PAGE 23 Updates Questions/Discussions Naming Binary Covalent Compounds § Binary means two, so two atoms § Compounds means atoms (at least two) that are bonded together Focus PAGE 24 Updates Questions/Discussions Naming Binary Covalent Compounds § In the two examples in the lab manual, 𝑆𝐹! and 𝑁" 𝑂# the least electronegative atom is written first (so sulfur and nitrogen) § Then simply add a prefix for how many atoms there are in the compound based on table 1 (mon = 1, di = 2 etc) Focus PAGE 25 Updates Questions/Discussions Naming Binary Ionic Compounds § Remember that ionic bonds are between metals (atoms on the left/middle) side of the period table and non-metals (right side) § The metal will be called its normal atom name. § Since it’s the least electronegative it’ll be named first § The non-metal has “-ide” added to the end. Focus PAGE 26 Updates Questions/Discussions Naming Binary Ionic Compounds § For transitional metals (labeled on the PT or found on the middle) you have to write the charge of the metal § First, figure out the charge of the non-metals § Since all oxygens create a -4 charge, the single lead is +4 Focus PAGE 27 Updates Questions/Discussions Naming Polyatomic or Complex ions § Similar to ionic, name the metal and non-metal § All the non-metals are part of a group listed on table 2 § Remember that The "ate" ion always has one more O atom than the "ite" ion. For example, SO4 2– is a sulfate Focus PAGE 28 Updates Questions/Discussions Quiz You’ll find your quiz on blackboard Questions/Discussions PAGE 29 Updates Focus