When Sulphur becomes Sulphide, it becomes negatively charged with 2 extra negative charges. It is S2-
A sulfur atom is a single sulfur atom while sulfide a sulfur atom with 2 extra electrons, giving it a 2- charge.
If you're talking about Iron (II) Sulfide, where the oxidation of Iron is 2+, 2 electrons from the Iron atom is transferred to the Sulfur atom, producing Fe2+ and S2- .
S + Cu => CuS