Metals are found in both free and combined states.
Reaction of metals with oxygen All metals combine
with oxygen with different rate to form metal oxides, e.g. sodium forms sodium oxide at room temperature on reacting with oxygen.
But copper forms copper oxide when it is heated in the presence of air.
Reaction of metals with water Metals like sodium react with cold water, magnesium with hot water and , iron with steam to form their hydroxides and evolve hydrogen gas.
Reaction of metals with acids Metals react with acids to form salt and evolve hydrogen gas, e.g. magnesium reacts with dilute hydrochloric acid to form magnesium chloride and evolve H2.