How many valence electrons are in a persulphate ion, ${\mathrm{SO}}_5^{2-}$ ?

The number of valence electrons are in a persulphate ion, ${\mathrm{SO}}_5^{2-}$ is 38.

Valence electron in sulphur is,s=6

No of oxygen atom is,n=5

Valence electrons in oxygen,O=6

Number of electrons gained,e=2

Total valence electrons in ${\mathrm{SO}}_5^{2-}$=  

$=\mathrm{s}+(\mathrm{n}\times \mathrm{o})+\mathrm{e}$

$=6+(5\times 6)+2$

$=38$

Hence the number of valence electrons are in a persulphate ion, ${\mathrm{SO}}_5^{2-}$ is 38.