Symbol : Cl,
Atomic Number — 17,
Mass Number — 35
Uses :
The chemical substances like bleaching powder, chloroform, etc. are manufactured by chlorine. It is also used as a drinking water purifier, as a germicide, in removing colours from the garments and cloths, in whitening sugar, etc. It is also used in the production of toxic gases like phosgene, mustard gas, etc.
Symbol : Br,
Atomic Number — 35,
Mass Number — 80
Uses :
In the production of salts of bromide, hypobromide, bromates etc. in making toxic and weeping gases, in the production of AgBr used in photography. It is also used as a reactant in organic chemistry, in the production of KBr, which is used in the form of sleeping drugs and pain reliever.
Symbol : I,
Atomic Number — 35
Uses :
It is used as a tincture of iodine and iodoform in the form of antiseptic and analgesic, lodex (compound of iodine) is used as an external application of pain reliever medicine of bone injuries. This is also used in the manufacturing of several dyes and drugs, and in the preparation of photographic paper, film, and plates. Iodine is also used as a stronger germicide (insecticide).