Question

Explain violet colour of iodine.

Answer 1

1. The violet colour of iodine is due to the absorption of visible light by iodine molecules.
2. Iodine molecules absorb light energy and excite their outer electrons to higher energy levels.
3. As the atomic size increases down the halogen group, excitation energy decreases; iodine, being larger, absorbs lower-energy visible light.
4. Iodine absorbs yellow and green light and transmits the complementary violet colour that we see.

Thus, the violet colour arises due to the specific wavelengths of light absorbed and transmitted by iodine molecules.