Metals occur in nature according to their reactivity. Low reactivity metals occur in free state.
Ex : Gold (Au), Silver (Ag).
Moderately reactive metals found in the earth's crust mainly as oxides, sulphides and carbonates.
Ex : Zincite (ZnO), Haematite , Galena (PbS).
So reactive metals never found in nature at free state.
Ex : Rock salt (NaCZ), Magnesite .