Question

Explain briefly how `+2` state become more and stable in the first half of the first row transition elements with increasing atomic number?

Answer 1

In all the element listed, with the removal of valenece 4s electrons (+2 oxidation state ), the 3d-orbitals get gradually occupied. Since the number of empty d-orbitals decrease or the number of unpaired electrons in 3d orbitals increase, the stability of the cations `(M^(2+))` increase from `Sc^(2+)` to `Mn^(2+)`