what are the charges on the metals?
MgSO4
NiSO4*6H2O
CoCl2*6H2O
could you just explain how you determined the first one? I can take it from there.
You can do it one of several ways.
1. Look at the periodic table. Mg is in group II. Mg is +2.
2. Look at the sulfate ion. If you've written very many formulas you know sulfate (SO4^2-) is -2. Since all compounds are zero charge, then Mg must be +2 to balance the -2 of sulfate.
3. S is in group VI. It is +6 (but you can't use this every time for S because S can be +4 and -2 as well as some oathers). O is -2 and there are four of them for -8 total. -8 from O and +6 from S means sulfate must be -2. Then Mg must be +2.
So, for NiSO4*6H20 the charge is +2, as well as for CoCl2*6H2O?
Or does the H2O play a role in the charge of the metal?
No, as you already know, I'm sure, H2O is zero; otherwise you would get zonked every time you took a drink of water. H2O is a compound and all compounds have a zero net charge (but the oxidation state of H in H2O is +1 for each and -2 for O).
You are right, both Ni and Co are +2 IN THOSE COMPOUNDS.