What is the chemical formula for chlorine?

The chemical formula for chlorine is represented as Cl₂. This notation indicates that chlorine exists as a diatomic molecule, meaning that two chlorine atoms bond together to form the most stable and common form of the element in its gaseous state. Chlorine is a halogen, and the diatomic nature is typical for elements in group 17 of the periodic table, allowing them to achieve stability through pairing.

Other options represent different substances altogether. NaCl is the chemical formula for sodium chloride, commonly known as table salt, which combines sodium and chlorine. HCl denotes hydrochloric acid, a compound formed from hydrogen and chlorine. CO₂ stands for carbon dioxide, consisting of one carbon atom and two oxygen atoms. Each of these formulas illustrates different chemical entities, but Cl₂ is specifically the chemical representation of elemental chlorine.