What is the ground-state electron configuration for ${\mathrm{O}}^{2-}$ ion?

Oxygen:

• Oxygen is a p-block element having an atomic number $8$ and an atomic symbol $\mathrm{O}$.
• It belongs to Group-$16$ and the second period.

Electronic configuration of Oxygen:

• The electronic configuration of Oxygen is $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^4$.

Electronic configuration of ${\mathrm{O}}^{2-}$ ion:

• The oxygen atom gains two electrons and results in the formation of ${\mathrm{O}}^{2-}$ion.
• The electronic configuration of ${\mathrm{O}}^{2-}$ ion is $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^6$.