Because copper's oxidation number is 2, and Sulfur's is 6, what does this tell you about the reaction they would make when heated together? What drew you to this conclusion? Thanks. :)
Copper is a metal and can lose 2 electrons to give the Cu+2 cation. Sulfur is a non-metal and can gain 2 electrons to give the S-2 anion. The compound formed is CuS.
