1. WARM UP “He who limps is still walking.” – Stanislav Lec
How can you apply this to life in the real world?
How can you apply this to your work in Chemistry?

2. Resonance Structures
Chemistry II

3. Resonance Structures Multiple possible Lewis structures
None are perfect, have charges on atoms
Molecule is a mixture of the structures

4. Resonance Structures Formal charge
Atoms in a molecule have a full charge because they have too many or too few bonds/e-
Polyatomic ions have overall charge

5. Resonance Structures Calculating for each atom
Valence e- - e- after bonding (bonds = 1 e-)
Difference = charge
Counting bonds
C likes 4, N likes 3, O likes 2
More bonds, + charge
Less bonds, - charge

6. WRAP UP Draw resonance structures for CO32-, showing formal charges.
Draw resonance structures for O3, showing formal charges.