Answer:
An Element is a substance made up of only one type of atom as like gold, copper, oxygen, etc.
Copper sulphate with molecular formula [tex](CuSO_4)[/tex], the elements are copper, sulphur and oxygen. It is formed by combination of [tex]Cu^{2+}[/tex] cation and [tex]SO_4^{2-}[/tex] anion.
Copper sulphide with molecular formula [tex](CuS)[/tex], the elements are copper and sulphur. It is formed by combination of [tex]Cu^{2+}[/tex] cation and [tex]S^{2-}[/tex] anion.
