The atomic number of chlorine is 17 and the mass is 35.45. The period number of chlorine is 3 and the group number is 17. Chlorine is in the halogen group and it is a gas. Chlorine is a non-metal.
DRINKING WATER CHLORINATION
Chlorine is used to purify drinking water.
WEAPON OF WAR
Chlorine gas was used during the war as a weapon.
Chlorine is used to brighten whites and remove stains.