In CuSO4, the oxidation state of copper Cu is +2.Here's the breakdown of the oxidation states for each element in the compound:- Copper Cu : +2- Sulfur S : +6 as it is in the sulfate ion, SO4 - Oxygen O : -2 there are four oxygen atoms, so the total is -8 The sum of the oxidation states in the compound must equal the overall charge of the compound, which is neutral in this case. So, +2 Cu +6 S + -8 O = 0.