To what extent do the electronic configurations decide the stability of oxidation states in the first series of the transition elements? Illustrate your answer with examples.
The elements in the first-half of the transition series exhibit many oxidation states with Mn exhibiting a maximum number of oxidation states (+2 to +7). The stability of +2 oxidation state increases with the increase in atomic number. This happens as more electrons are getting filled in the d-orbital.
However, Sc ([Ar] 3d14s2) does not show +2 oxidation state, instead, it loses all the three valence electrons to form Sc3+. The +3 oxidation state of Sc is very stable as it attains stable configuration.
For Mn ([Ar] 3d54s2), +2 oxidation state is very stable because after losing two electrons, it attains stable half-filled structure.