1. Ionic Compounds
The Rules!

2. The IONS
Metallic elements lose their valence electrons to become positive ions
ie. Sodium (Na): VE =1; loses it to become Na+
Gallium (Ga): VE = 3; loses them to become Ga+3

3. The IONS
Non-metallic elements add valence electrons to get to a total of 8 valence electrons to become negative ions
ie. Bromine (Br): VE = 7; gains 1 valence electron to get a total of 8; becomes Br-
Phosphorous (P): VE = 5; gains 3 valence electrons to get a total of 8; becomes P-3

4. The IONS
Sometimes 2 or more elements combine to form a polyatomic ion.
ie. S and O form SO4-2
N and H form NH4+

5. Ionic Compounds: Rules for making Ionic Compounds#1
Only positive and negative ions will bond

6. Ionic Compounds: Rules for making Ionic Compounds#2
The positive ion is always listed first

7. Ionic Compounds: Rules for making Ionic Compounds#3
You must combine enough positive and
negative ions together to make neutral
compounds

8. Ionic Compounds: Rules for making Ionic Compounds#4
Polyatomic ions are never changed

9. Ionic Compounds: Rules for making Ionic Compounds#5
If you have more than 1 particle of a
polyatomic ion you must surround the ion
with parentheses
ie. NH4+ and SO form the compound
(NH4)2SO4