Iodine has an atomic number of 53, which means it has 53 electrons.
The electron configuration of iodine in its ground state is [Kr] 5s^2 4d^10 5p^5.
When iodine forms an ion, it typically gains one electron to become a negatively charged ion with a charge of -1.
The subshell electron configuration of the iodine ion would be [Kr] 5s^2 4d^10 5p^6, as it now has one additional electron compared to the neutral iodine atom.