The number of valence electrons in ${\mathrm{O}}^{2-}$ ion is

The correct option is D

$8$

The explanation for the correct option

(D) $8$

Valence electrons

• The electrons that are added to the electronic shell with the highest principal quantum number are called valence electrons.

Number of valence electrons in ${\mathrm{O}}^{2-}$ ion

• The atomic number of oxygen is $8$.So, the number of electrons in oxygen is $8$.
• The number of electrons in ${\mathrm{O}}^{2-}$is $10$.
• So, the electronic configuration of ${\mathrm{O}}^{2-}$is $1s^{2}2s^{2}2p^6$.
• The valence electrons in ${\mathrm{O}}^{2-}$ is $8$.

Hence, the correct option is (D) $8$.