Final answer:
The electron configuration of an iodide ion (I−) is [Kr]4d10 5s2 5p6, indicating that it has gained an extra electron in the 5p orbital compared to the neutral iodine atom.
Step-by-step explanation:
The question asks for the electron configuration of the iodide ion (I−). The electron configuration of an element or ion shows the distribution of electrons among the orbitals of an atom. For the neutral iodine atom (I), the electron configuration ends with 5p5. Since the iodide ion has gained an extra electron compared to the neutral atom, the additional electron will fill the 5p orbital. Thus, the electron configuration for I− is [Kr]4d105s25p6.