Question

Which is less reactive, iodine or oxygen?

Answer 1

Iodine

Iodine is a grayish black solid and is the least chemically active of the four; however, among the nonmetals only oxygen is more reactive than iodine. Pure halogens exist as diatomic molecules, e.g., Cl2; they form interhalogen compounds, i.e., compounds between two halogens.