* Element: A pure substance consisting of only one type of atom. Oxygen (O) is an element.
* Compound: A substance formed when two or more different elements chemically combine in a fixed ratio. O3 is not a compound because it consists of only one element (oxygen).
* Atom: The smallest unit of an element that retains the chemical properties of that element. O is the symbol for a single oxygen atom.
* Molecule: Two or more atoms bonded together. O3 is a molecule because it consists of three oxygen atoms bonded together.
* Mixture: A combination of two or more substances that are not chemically bonded. O3 is not a mixture.
* Substance: A pure form of matter with a definite and uniform composition. O3 is a substance.
Therefore, O3 is a molecule and a substance.
It's important to note that O3 is specifically called ozone, a form of oxygen with three atoms per molecule. It's a distinct substance with its own unique properties.
