Here's why:

* Electron Configuration: Iodine's electron configuration is [Kr] 4d¹⁰ 5s² 5p⁵.

* Valence Electrons: Valence electrons are the electrons in the outermost shell of an atom. For iodine, this is the 5th shell (n=5), which contains the 5s and 5p orbitals.

* Counting: There are 2 electrons in the 5s orbital and 5 electrons in the 5p orbital, totaling 7 valence electrons.