## Chemistry: The Molecular Science (5th Edition)

The ion is $Fe^{2+}$. Its ground state configuration is $[Ar]4s^{2}3d^{6}$. 4s electrons are at a higher energy level. Iron loses two 4s electrons to form the $Fe^{2+}$ ion. The $V^{2+}$ ion will have three 3d electrons, as it loses its two 4s electrons to form the $V^{2+}$ ion.