What is the ionic formula for magnesium oxide?

1 Answer

The ionic formula for magnesium oxide is MgO.

Why is this the case?

The Magnesium ion is an Alkaline Earth Metal and wants to give up the 2 s orbital elections and become a +2 cation.

Oxygen has six valence electrons and is looking to gain two electrons to complete the octet (8) electron count in the valence shell making it a -2 anion.

When the charges of the Magnesium +2 and the Oxygen -2 are equal and opposite, the ions for an electrical attraction. (Remember Paula Abdul told us "Opposites Attract")

This one to one ratio of charges makes the formula MgO.