F₂ absorbs ........ portion of light and appear yellow and I₂ absorbs .......... portion of light and appears violet

Halogens absorb the visible radiation and consequently their electrons are excited.

The energy for excitation depends upon the size of halogen molecule.

Fluorine has smallest size among halogens. It requires high energy for excitation. It absorbs high energy violet-indigo radiation and hence appears yellow.

On the other hand, iodine is larger in size. It requires relatively less energy for excitation. It absorbs, low energy orange-red radiation and hence appears violet