Question

The magnetic moment of ${}_{25}Mn$ in ionic state is $\sqrt{15}BM$, then $Mn$ is in:

• A. +2 state
• B. +3 state
• C. +4 state
• D. +5 state

Answer 1

The correct option is C +4 state

The magnetic moment can be calculated by the formula $\left[n\right(n+2){]}^{\frac{1}{2}}$
Where n=number of unpaired electron.
Since magnetic moment is $\sqrt{15}BM$, so n=3
The electronic configuration of $Mn=\left[Ar\right]4s^{2}3d^5$.
We need 3 unpaired electrons, thus $Mn$ is in +4 oxidation state.