Question

Scandium shows only two oxidation states. Explain.

Answer 1

Scandium has electronic configuration, ₂₁Sc : 1s², 2s², 2p⁶, 3s², 3p⁶, 3d¹, 4s² 

Sc shows only two oxidation states namely +2 and +3.

(1) Due to the loss of two electrons from the 4s-orbital, Sc acquires +2 oxidation state Sc²⁺ : 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹

(2) Due to the loss of one more electron from the 3d-orbital, it acquires +3 oxidation state with the extra stability of an inert element Ar.

Sc +3 : 1s² 2s² 2p⁶ 3s² 3p⁶ 

(3) Since Sc³⁺ acquires extra stability of inert element [Ar], it does not form higher oxidation state.