# Can an atom lose more than one electron to another atom in ionic bonding?

Let's take a look at the ionic compound magnesium oxide $\left(\text{MgO}\right)$. The magnesium atom needs an octet of electrons in its valence shell, and so does oxygen. The neutral magnesium atom has two valence electrons in the third energy level, and the neutral oxygen atom has six valance electrons in the second energy level.
So if the magnesium atom transfers its two valence electrons to the oxygen atom, both will have an octet in their valence shells, and the magnesium atom becomes a magnesium ion with a 2+ charge $\left(\text{Mg"^(2+)}\right)$, and the oxygen atom becomes an oxide ion with a 2- charge $\left(\text{O"^(2-)}\right)$. By losing its two valence electrons, magnesium's valence shell is now in the second energy level, which contains eight valence electrons.