1. When Metals Have More Than One Cation

2. Some transition metals can have more than one cation
Some transition metals can have more than one cation. For example, copper can have a +1 or a +2 charge.
We can tell the charge of the metal because it is written in as a roman numeral in the name. This is called the stock system for naming.

3. E.g. write the formula for copper (I) sulfide
Cu S2-
Cu2S

4. E.g. write the formula for copper (II) sulfide
Cu S2-
CuS

5. Naming and the Stock System
We can find the name of a compound using the stock system.
We use a reverse criss-cross method

6. Naming and the Stock System
FeCl3
Iron can have a +2 or a +3 charge.
Fe? Cl1-
There are 3 negative charges, therefore Fe must be +3.
We would call it Iron (III) chloride.

7. Naming and the Stock System
Cu2S
Copper can have a +1 or a +2 charge.
2 Cu? S2-
Two atoms of Copper (I) will make a 2+ charge (1+ x 2 atoms of Cu= 2+).
We would call it Copper (I) sulfide.