Explain the formation of ozone in the atmosphere.

Ozone is formed by the action of ultraviolet rays of the Sun on oxygen.

3O₂ (g) ⟶ 2O₃ (g)

High energy ultra violet radiation, help in breaking oxygen molecules into oxygen atoms.

O₂ + UV ⟶ O + O

Oxygen atoms then react with oxygen molecule to form ozone.

O + O₂ ⟶ O₃

Net reaction : 3O₂ + UV ⟶ 2O₃