What is a molecule composed of two atoms bonded together called?

A molecule composed of two atoms bonded together is specifically referred to as a diatomic molecule. The term "diatomic" comes from the prefix "di-", meaning two. Diatomic molecules consist of two atoms, which can either be of the same element or different elements. Examples include hydrogen (H₂), oxygen (O₂), and nitrogen (N₂).

This classification is significant in both chemistry and physics as it helps in understanding molecular structures, behaviors, and interactions in various chemical reactions. In contrast, monatomic molecules consist of a single atom and therefore do not comprise two bonded atoms. Polyatomic molecules contain three or more atoms bonded together, and homonuclear molecules consist of two or more atoms of the same element.

Diatomic molecules play an important role in various chemical processes and contribute to the fundamental understanding of molecular chemistry.