What is the molecular formula of Ozone?

The story behind the answer

Ozone is O3, a triatomic allotrope of oxygen. Unlike O2, ozone’s bent three-atom structure makes it highly reactive and gives it a sharp, distinctive smell. In the stratosphere it forms the ozone layer, absorbing harmful UV radiation; near the ground it’s a pollutant formed by sunlight acting on emissions.

Remember: “Ozone has three O’s” = O3. The other options are different substances: N2O is nitrous oxide (laughing gas), C6H2O6 resembles glucose’s formula but is incorrect (glucose is C6H12O6), and SO4 is the sulfate ion (usually written SO4^2−), not a neutral molecule.