Question

iodine is a non metal.but it is lustrous

Answer 1

I think its because going down the group the size of the atom increases because of shielding effect due to which the ineraction between the atom and the outermost electron decreases so these electrons on the surface of iodine become excited by absorbing heat energy from light so when they release this energy and come ...

hop,,,,it helps

Answer 2

$ASSALAMUALAIKUM$

Iodine is a mettaloid i.e,it has properties between metals and non metals . Therefore it possesses some properties of ametal too like being lustrousi.e,to shine and brittle i.e,hard butliable to break easily.

$INSHAALLAH it will help you!$