## Chemistry: Molecular Approach (4th Edition)

(a) $~Fe,\text{ }Sc$ (b) $~Mn$ (c) $Ti$
(a) The first-row transition metals that have $+3$ as the highest possible oxidation state are as follows: \begin{align} & Fe:\quad \left[ Ar \right]3{{d}^{6}}4{{s}^{2}};\quad \quad F{{e}^{3+}}:\quad \left[ Ar \right]3{{d}^{5}} \\ & Sc:\quad \left[ Ar \right]3{{d}^{1}}4{{s}^{2}};\quad \quad S{{c}^{3+}}:\quad \left[ Ar \right] \\ \end{align} (b) The first-row transition metal that has $+7$ as the highest possible oxidation state is as follows: $Mn:\quad \left[ Ar \right]3{{d}^{2}}4{{s}^{2}};\quad \quad M{{n}^{7+}}:\quad \left[ Ar \right]$ (c) The first-row transition metal that has $+4$ as the highest possible oxidation state is as follows: $Ti:\quad \left[ Ar \right]3{{d}^{2}}4{{s}^{2}};\quad \quad T{{i}^{4+}}:\quad \left[ Ar \right]$