When oxygen and aluminum form an ionic compound, what is the formula?

The correct answer is

D. al2O3

Explanation:

The offense in electronegativity is subject for the ionic bonds in aluminum and oxygen, Ionic bonds are created between cations and anions. A cation is formed when a metal ion spends a valence electron while an anion is produced when non-metal gains a valence electron. They both achieve a more stable electronic arrangement through this change.

Al2O3

O has 2 and Al has 3