1. Announcements Be respectful – no electronics please!
There is discussion on Friday!
Pre/post lecture assignments due as usual Tuesdays & Thursdays at 8:00 am
Lon-Capa Homework Due Wednesday at 10:00 pm
Lab & Textbook homework due Friday
Exam 3 is on Thursday December 6!

2. Overall goal: Atomic Structure Chemical Bonding 3D Molecular Structure
Molecular Properties

3. Electronegativity

4. Types of Bonding Ionic Bonding Polar Covalent Bonding
Nonpolar Covalent Bonding

5. Clicker #1
Arrange the following bonds from the least polar to the most polar bond.
C–F, Na–F, Ge–F, Si–F
a) C–F < Ge–F < Si–F < Na–F
b) Si–F < C–F < Ge–F < Na–F
c) C–F < Si–F < Ge–F < Na–F
d) Na–F < Ge–F < Si–F < C–F
e) Na–F < C–F < Si–F < Ge–F

6. General Guidelines…
The total number of electrons in your Lewis structure must equal the total number of valence electrons.
The least electronegative atom (usually written first) is typically the central atom (except for hydrogen).
Follow the octet rule.
Follow the duet rule for hydrogen.
Trial and error – add double and triple bonds as necessary until octet (or duet) rule is satisfied & valence electrons add up.

7. A good Thanksgiving break read!
The Poisoner’s Handbook by Deborah Blum
You will recognize a lot of compounds!

8. General Guidelines…
The total number of electrons in your Lewis structure must equal the total number of valence electrons.
The least electronegative atom (usually written first) is typically the central atom (except for hydrogen).
Follow the octet rule.
Follow the duet rule for hydrogen.
Trial and error – add double and triple bonds as necessary until octet (or duet) rule is satisfied & valence electrons add up.

9. Clicker #2
Draw Lewis structures for each of the following substances. How many contain a double bond?
HF CN- SO Cl2
A) 0
B) 1
C) 2
D) 3
E) 4

10. Clicker #3 Draw Lewis structures for both HCN and CO32-.
Which displays resonance?
A) HCN
B) CO32-
C) Both
D) Neither