Chemistry: Oxidation?

[AgaBoogaBoo]

I need help figuring out the the oxidation numbers for these:

MgSO4 - we can place the known oxidation number for O, but how do we get it for MG and S?
K2S
Cu2S

We are given oxidation numbers for Fluorine, Oxygen, and Hydrogen.

If I can get help on those, I can figure out the rest of them like those.

 

[WinkOsmosis]

Mg is +2 because it's in group II. And maybe S is the same as oxygen, and that would override the group #. K is also group II.

 

[LS20]

Originally posted by: AgaBooga
I need help figuring out the the oxidation numbers for these:

MgSO4 - we can place the known oxidation number for O, but how do we get it for MG and S?
K2S
Cu2S

We are given oxidation numbers for Fluorine, Oxygen, and Hydrogen.

If I can get help on those, I can figure out the rest of them like those.

the oxidation numbers of the compound should total 0, unless a diff charge is specified

 

[fatalbert]

the sulfate ion SO4 is -2 total, so S=+6, Mg=+2 at stated above

K=+1 always, since it is a Alkali Metal, and now S=-2

here S=-2 because that is its most common state, and Cu=+1