Answer:
Ozone is a compound.
Explanation:
Elements are simple atoms that can merge or combine to produce a bigger molecule called a compound. They can not be splitted into smaller atoms. Examples are: hydrogen, carbon, etc.
A compound is formed as a result of the combination of two or more elements. They can be splitted into elements. Examples are: ammonium, water, carbon dioxide etc.
Ozone ([tex]O_{3}[/tex]) is a less stable allotrope of oxygen which is made up of three atoms of oxygen. Therefore, it is a compound.