Question

the least active element in group 17 is

Explanation:

In Group 17 (halogens), reactivity decreases down the group. Fluorine is the most reactive and iodine is the least reactive among them due to the increase in atomic size and shielding effect as we move down the group, which makes it harder for iodine to gain an electron compared to the lighter halogens.

Answer:

Iodine