Q. Which one of the following ions exhibits d-d transition and paramagnetism as well ?
A) $MnO_4^-$
B) $Cr_2O_7^{2-}$
C) $CrO_4^{2-}$
D) $MnO_4^{2-}$
Explanation
[Solution] In $MnO_4^{2-}$ Mn is +6 ($3d^1$): one unpaired electron allows d-d transition and paramagnetism. The others are $d^0$. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.