Chemical formula of magnesium oxide is ________.

MgO

The correct answer is option 3. MgO.

Magnesium oxide \((MgO)\) is a chemical compound composed of magnesium \((Mg)\) and oxygen \((O)\). In its simplest form, magnesium oxide consists of one magnesium atom and one oxygen atom. The chemical formula MgO reflects this composition.

Magnesium oxide is commonly known as magnesia and occurs naturally as the mineral periclase. It is often produced by heating magnesium carbonate or magnesium hydroxide. The resulting white solid, magnesium oxide, has a range of applications, including as a refractory material, in the production of magnesium metal, and as a component in various medical and dietary supplements.