1. Chemistry-Part 2 Notes Chemical Bonding

2. What are Chemical Bonds?
A chemical bond is a force that holds two atoms together.
Why Bond?
Makes atom more stable.
Obtain Noble Gas Configuration (8 Valence electrons) through sharing, gaining, or losing valence electrons.

3. Ionic Bonds
Involves a metallic cation (positively charged) and a non-metallic anion (negatively charged).
Metals are always written first.
The number of electrons gained must equal the number of electrons lost.

4. Oxidation Numbers
Oxidation Numbers: The number of the transferred electrons from an atom to another atom. It is the same as a charge.
“How many electrons must be gained/lost for the atom to reach noble gas configuration?”
Group #: 1A 2A 3A 4A 5A 6A 7A 8A
Valence e-:
Oxidation #: /
Example: What are the oxidation numbers for:
F Ca -1 +2

5. Forming Ionic Bonds
Oxidation Numbers: MUST MATCH! This tells you how many of each atom are needed to form the bond.
In order for Fluorine and Calcium to bond, how many of each molecule do we need?
F Ca
Oxidation Number: _-1___ _+2___
Molecules Needed: __2__ __1__
Show The Bond:

6. Another Example Na N Oxidation Number: __+1__ __-3__
Molecules Needed: __3__ __1__
Show The Bond: