1. Variable charge metals
Ionic Compounds

2. Variable Charge Ions
Some elements in the transition metals can form more than one type of ion. Sometimes they may lose 2, 3, 4 or even more electrons in order to bond with another element.
So these metals can form +2, +3 ,+4 etc cations in one compound but have a different charge in another compound. In order to tell them apart we name them differently.

3. Writing the formula
When given the name of the compound, the Roman numeral after the metal tells us the CHARGE of the metal.
Copper II Chloride – means Cu+2 Cl-1
Follow the same steps as before >>>>
1. Write out the charges
2. Criss-cross
3. Combine as a formula unit (get rid of charges on top)
4. Simplify if needed

4. Multiple Oxidation States
“tin fluoride”
Tin is either 2+ or 4+ oxidation state.
tin (II) fluoride
tin (IV) fluoride
Sn2+
F1-
Sn4+
F1-
SnF2
SnF4
tin (II) sulfide
Sn2+
S2-
Sn2S2
SnS

5. B. To find the formula, given the name:
1. Write symbols for the two types of ions.
2. Balance charges to write formula. Co Sn
cobalt (III) chloride
Co3+
Cl1–
CoCl3
tin (IV) oxide
Sn4+
O2–
SnO2
tin (II) oxide
Sn2+
O2–
SnO

6. Lets Practice some – Lead (IV) oxide Mercury (II) Chloride
Bismuth (III) sulfide
Iron (II) Bromide
Copper (II) Chloride
Titanium (III) phosphide
Lead (II) oxide

7. When naming….
You need to work backwards from the formula to find the charge of the metal. 1. First write the charge (oxidation state) of the nonmetal (Anion) 2. Multiply the charge by its subscript. 3. The charge (oxidation state) of your cation (metal) multiplied by its subscript needs to equal this number. 4. Write the name of the compound as usual, then change the charge of the metal into a roman numeral, put into parentheses and put it after the name of the metal.

8. A. To name, given the formula:Cu Fe
Figure out charge on
cation.
2. Write name of cation.
3. Write Roman numerals
in ( ) to show cation’s charge.
Stock System
of nomenclature
4. Write name of anion.
FeO
iron oxide
Fe?
Fe2+
O2–
iron (II) oxide
Fe2O3
Fe?
iron oxide
Fe3+
Fe?
Fe3+
O2–
O2–
O2–
iron (III) oxide
CuBr
copper bromide
Cu?
Cu1+
Br1–
copper (I) bromide
CuBr2
Cu?
copper bromide
Cu2+
Br1–
Br1–
copper (II) bromide

9. Let’s practice
1. FeCl3
2. CuO
3. Cr2O3
4. NiS
5. V2O5