What is the electron dot diagram for magnesium oxide?

May 15, 2016

Well, magnesium oxide is an ionic species, which we could represent as $M {g}^{2 +} {O}^{2 -}$.

Explanation:

Elemental magnesium has 12 nuclear protons, $Z = 12$. It has 2 valence electrons that are conceived to be lost when it undergoes oxidation to $M {g}^{2 +}$.

$M g \rightarrow M {g}^{2 +} + 2 {e}^{-}$ $\left(i\right)$

Elemental (atomic!) oxygen has 8 electrons, $Z = 8$. The oxide anion thus has 10 electrons upon reduction:

$O + 2 {e}^{-} \rightarrow {O}^{2 -}$ $\left(i i\right)$

So $\left(i\right) + \left(i i\right) =$

$M g \left(s\right) + \frac{1}{2} {O}_{2} \left(g\right) \rightarrow M g O \left(s\right)$