## Chemistry: Molecular Approach (4th Edition)

When a transition metal forms an ion, it loses electrons first from the ns orbital before losing electrons from the $\left( n-1 \right)\text{d}$ orbital. For example, Fe has an electron configuration of$[Ar]3{{d}^{6}}4{{s}^{2}}$ and during the formation of Fe2+ it loses both the 4s electrons.