Question

the halogens are coloured. why?

Answer 1

Halogens have an unpaired electron that is present in the outermost shell (valence shell) of the atom. When photons (light particles) of suitable energy hit the atom, the electron gets excited and moves to higher energy states in the atom. they absorb energy from visible region and show the complimentary colour.

Answer 2

Hey !!

All Halogens are coloured. This is due to absorption of radiation in visible region which results in the excitation of outer electrons to higher energy level while the remaining ligh is transmitted. The colour of the halogen is the colour of transmitted light.

Hope it helps you !!