There are two categories of metal.-

Ferrous
Ferrous metals are alloys of iron and other elements. Steels contain carbon which affects their ability to be hardened. Stainless steel contains Chromium which stops rusting. Rusting can also be prevented by - painting, plastic dip coating, galvanising, coating in oil or grease.

Non Ferrous
Non Ferrous metals do not contain iron. Common example are copper, aluminium, silver, gold. There are many non ferrous alloys - brass is copper and zinc, bronze is copper and tin, solder is lead and tin.

Ther is a lot more detailed information under engineering materials about plastics and metals.