Colour of halogens

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Colour - 

 Halogens are coloured. F² Is light yellow, Cl² is greenish yellow, Br² is reddish brown and iodine is deep violet. The colour of the halogens is due to the fact that their molecules absorb visible light which excite their electrons to higher energy states. Again the difference in the colour of the halogens can be attributed to their size which is tunn may be due to their difference in their ionization potential. As IP decrease, the excitation energy decrease and thus colour changes from high energy radiation to low energy radiation. The colour of the F² is light yellow which is the complementary colour of the violet because it absorb high energy radiation  i.e., violet light. I² is violet, which is the complementary colour of the yellow because it absorb low energy radiation i.e yellow light.

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