1. UNIT VIII Lewis Structure Lesson 5

2. Lewis Structure

4. Gilbert Newton Lewis Invented “Electron-dot” formulas or “Lewis Structures” I’m so tired of writing all those useless inner electrons, in the Bohring models!

5. Valence Electrons – electrons in the outermost occupied energy level. (s and p electrons outside the core) Valence electrons can be represented by “dots” drawn around the atom.

6. Remember the rules…

7. VIII.3 CHEMICAL BONDING C. Writing Lewis Structures a. Simple Ionic Compounds: Draw the Lewis Structure of: a) MgO

8. VIII.3 CHEMICAL BONDING b)KCl c) CaF 2

9. VIII.3 CHEMICAL BONDING b. Covalent Compounds: Octet Rule : most atoms, other than hydrogen, tend to attain an octet of electrons as a result of forming covalent bonds

10. VIII.3 CHEMICAL BONDING Rules: 1. Count the TOTAL # of valence e- (Subtract 1 e- for every positive charge, and add 1 e- for every negative charge on the molecule.) 2. Determine which atoms are bonded together, put 2 e- into each bond 3. Use the remaining valence e- to complete the octets of the atoms surrounding the central atom 4. If central atom has less than an octet of e-, have a neighbour share e- with the “deficient atom” by putting an extra pair of e- 5. Replace each pair of e- with a dash

11. VIII.3 BONDING Ex. 1 CH 4

12. VIII.3 BONDING Ex. 2 NH 4 +

13. VIII.3 BONDING Ex. 3 O 2

14. VIII.3 BONDING Ex. 4 NO +

15. VIII.3 CHEMICAL BONDING Ex. 5 CHO 2 -

16. O NE LAST TO TRY HPO 2

17. H OMEWORK ON L EWIS STRUCTURE Homework p. 183 #85 p. 188 # 86a-u