Chemical reactivity of metals with air

  • When metals are burnt in air, they react with the oxygen of the air to form metal oxides.
  • Metal oxides are basic in nature.



Potassium and Sodium

Metals such as potassium and sodium react so vigorously that they catch fire if kept in the open. Hence, to protect them and to prevent accidental fires, they are kept immersed in kerosene oil.

Magnesium, Aluminium, Zinc, Lead

At ordinary temperature, the surfaces of metals such as Magnesium, Aluminium, Zinc, Lead, etc., are covered with a thin layer of oxide. The protective oxide layer prevents the metal from further oxidation.


Iron does not burn on heating but iron filings burn vigorously when sprinkled in the flame of the burner.


Copper does not burn, but the hot metal is coated with a black coloured layer of copper(II) oxide.

Platinum and Gold 

Platinum and gold do not react with oxygen even at high temperatures.

Chemical reactivity of metals with water 

Metals react with water and produce a metal oxide and hydrogen gas. Metal oxides that are soluble in water dissolve in it to further form metal hydroxide. But all metals do not react with water.



Potassium and sodium

They react violently with cold water. In case of sodium and potassium, the reaction is so violent and exothermic that the evolved hydrogen immediately catches fire.


The reaction of calcium with water is less violent. The heat evolved is not sufficient for the hydrogen to catch fire.

Calcium starts floating because the bubbles of hydrogen gas formed stick to the surface of the metal.


Magnesium does not react with cold water. It reacts with hot water to form magnesium hydroxide and hydrogen. It also starts floating due to the bubbles of hydrogen gas sticking to its surface.

Aluminium, iron and zinc

Metals like aluminium, iron and zinc do not react either with cold or hot water. But they react with steam to form the metal oxide and hydrogen

Lead, copper, silver and gold

Metals such as lead, copper, silver and gold do not react with water at all


Chemical reactivity of metals with acids 

  • Metals react with acids to give a salt and hydrogen gas.
  • Copper, mercury and silver do not react with dilute acid.
  • Metal + Dilute acid → Salt + Hydrogen



  • Nitric acid is a strong oxidizing agent. 
  • It oxidize hydrogen gas to water and itself gets reduce to nitrogen oxides (NO , NO2 , N2O)

  • Hydrogen gas is not evolved when metals react with dilute nitric acid. 
  • But magnesium (Mg) and manganese (Mn) react with very dilute HNO3 to evolve H2 gas.

 Aqua regia(Latin for ‘royal water’)

  • It is a freshly prepared mixture of concentrated hydrochloric acid and concentrated nitric acid in the ratio of 3:1.
  • It can dissolve gold, even though neither of these acids can do so alone.
  • Aqua regia is a highly corrosive, fuming liquid.
  • It is one of the few reagents that is able to dissolve gold and platinum.


Chemical properties of Non-metals-

  • Non-metals are electronegative in nature.  They have a tendency to accept electrons and form a negatively charged ions.
  • Non-metals react with oxygen to form covalent oxides. Such oxides are either neutral or acidic in nature.
  • Non-metals react with halogens to give covalent halides. In pure state, the halides of non-metal do not conduct electricity.
  • Non-metals react with hydrogen to give covalent hydrides. The hydrides of non-metal may be acidic , basic or neutral depending upon the nature of the non-metals. For example – ammonia is basic in nature, water is neutral and hydrogen sulphide is weakly acidic in nature.

Non-metals do not displace hydrogen from dilute acids