Question

For each metal that had a chemical change, write the type of metal it is based on examination of the periodic table.
These are the metals that had chemical change:
NH4OH and Fe(NO3)3
NH4OH and Co(NO3)2
NH4OH and Cu(NO3)2
NH4OH and Zn(NO3)2

Answer 1

If you look at where these metals are, you should find these in the middle block known as transition metals.

Answer 2

I don't know if I did this right but:
NH4OH - Ammonium Hydroxide
Fe(NO3)3 - Iron(III) Nitrate
Co(NO3)2 - Cobalt(II) Nitrate
Cu(NO3)2 - Copper (II) Nitrate
Zn(NO3)2 - Zinc Nitrate
Are these correct and if they are how do I know where to look for them on the periodic table?

Answer 3

@mach_15 yes your formulae are correct/
The transition metals often have variable oxidation states (valencies). Your Roman numerals denote these states. So really the position of the metal cation on the periodic table doesn't exactly help you for these. Generally the oxidation states tend to vary between I to IV.
II is very common, and some like Iron have III as an oxidation state as well. States can also change in a reaction. In fact if you do form a precipitate of iron (ii) hydroxide Fe(OH)2, it commonly oxidises in the air to form the III oxidation state, giving Fe(OH)3.
Lead can have II or IV, as with Manganese (actually Mn has more than this), and mercury typically has I and II oxidation states.

You will become familiar with the common oxidation states with time but they almost always tell you what the states will be.

Sometimes the states might be implied in the NAME of the compound. For instance ferric oxide is iron (III) oxide or Fe2O3 while ferrous oxide is Iron (II) oxide or FeO.

General naming rule:
-ic metal cation suffix = more oxidised, higher oxidation number, more oxygens
eg. cupric
-ous metal cation suffix = less oxidised, lower oxidation number, more oxygens
This naming convention is not quite common because of potential ambiguity so oxidation number is generally more helpful.