1. Covalent Bonds Multiple bonds!

2. Multiple Covalent Bonds Some elements can share more than one pair of electrons Double covalent bond: sharing 2 pair (4) electrons Triple covalent bond: sharing 3 pair (6) electrons Multiple bonds: double or triple covalent bonds (more than one shared pair of electrons)

3. Multiple bonds Can be common for carbon, nitrogen and oxygen atoms

4. Multiple Bonds Do NOT occur for all atoms

5. Do Sample Problem 6-4 Draw the Lewis structure for methanol CH 2 OH (AKA formaldehyde) Draw the Lewis structure for carbon dioxide CO 2 Draw the Lewis structure for hydrogen cyanide, HCN

6. Resonance If multiple bonds exist, the molecule's structure was thought to vary between two (or more) forms Example: ozone Now we believe the 'true' structure is the average of the possible structures (making a resonance structure) Resonance: bonding in molecules or ions that cannot be correctly represented by a single Lewis structure

7. Test Your Skills Draw Lewis structures for: IBr CH 3 Br C 2 HCl SiCl 4 F 2 O