The Lewis structure of diatomic iodine is two iodine atoms sharing a single bond, with each atom also containing three lone pairs. Iodine is in group 17 on the periodic table, meaning that iodine needs only a single electron to become chemically stable.
Because iodine only needs one electron, it readily accepts electrons. The sharing of a valence electron in diatomic iodine allows the atoms to exist together as a stable molecule, although it reacts readily with a range of compounds and elements. There are seven elements that exist in a diatomic state: hydrogen, oxygen, nitrogen, fluorine, chlorine, bromine and iodine.