Question

The formal charge on $Mn$ in $Mn{O}_4^{-}$ is:

• A. 0.0
• B. -1
• C. 7
• D. 1

Answer 1

The correct option is A 0.0

Formal charge on any atom is calculated as:
Formal charge $\left(FC\right)$ = $V-L-\frac{B}{2}$
Where,
$V$ = Total number of valence electrons in the valence shell of the atom.
$L$ = Total number of non bonding (lone pair) electrons of the atom.
$B$ = Total number of bonding (shared) electrons of that particular atom.
For d block elements, number of valence electrons = (n-1)d + ns electrons.
From the given structure for manganese, we have $V=7;L=0;B=14$

$\therefore$ Formal charge on the $Mn$ atom in $Mn{O}_4^{-}$ is:
$FC=7-0-\frac{1}{2}\times \left(14\right)\therefore FC=0$