JEE Main 2015 — d and f Block Elements Question with Solution

Charge transfer from  ${\text{O}}^{2-}$ to empty $\text{d}$ -orbitals of metal ion ${\text{(Mn}}^{7+}).$
The colour in ${\text{KMnO}}_{\text{4}}$ arises from an electronic transition. In the permanganate ion ${\text{(MnO}}_{\text{4}}^{-}\text{),}$ manganese is in the $+7$ oxidation state, so it has no $\text{d}$ electrons. Photons promote an electron from the highest energy molecular orbital to an empty $\text{d}$ -orbital on the manganese. When a photon of light is absorbed, this charge transfer takes place from $\text{L}$ to $\text{M}\text{.}$