Metals are elements and are good conductors of heat and electricity. Most of the metals are electropositive in nature and the metal atoms lose electrons in chemical reactions to form cations. The more reactive a metal, the greater tendency it has to form a positive ion in a chemical reaction. A more reactive metal readily reacts with other elements. The most reactive metals will react even with water while the least reactive metals will not react even with acid.
This video explains the action of Zn, Fe, Cu and Mg metals on the solutions of copper sulphate, zinc sulphate solution, aluminium sulphate and silver nitrate.