The correct formula for magnesium oxide is MgO.
Magnesium oxide is formed when magnesium (Mg) reacts with oxygen (O2). In this reaction, one magnesium atom combines with one oxygen atom to form magnesium oxide. The balanced chemical equation for this reaction is:
2Mg + O2 → 2MgO
This means that two magnesium atoms react with one oxygen molecule to produce two units of magnesium oxide. The formula MgO indicates that the compound consists of one magnesium ion (Mg2+) and one oxide ion (O2-), which combine in a 1:1 ratio to form a stable compound.