1. Chemistry 141 Wednesday, November 8, 2017 Lecture 27
Chemistry 11 - Lecture 11
9/30/2009
Chemistry 141
Wednesday, November 8, 2017
Lecture 27
Lewis Structures and Ionic Bonds

2. Drawing Lewis Structures
Sum the valence electrons in the molecule (or ion – correct for charge)
Arrange and write the atomic symbols. Connect atoms with a single line to indicate a bond.
Use dots to complete octets around the peripheral atoms (except H, which has 2).
Place any remaining electrons as lone pairs on the central atom
If there are not enough electrons for the central atom to have an octet, try forming multiple bonds.
Calculate formal charges:
Formal charge = valence electrons – ½ (bonding electrons) – all nonbonding electrons

3. The Best Lewis Structure?
Start here 6/11/10

4. Average Bond Enthalpies

5. Bond lengths