_________ is an example of a compound molecule.

• A. Water
• B. Common table salt
• C. Oxygen
• D. Glucose

Answer: (B)

A compound is a substance formed from two or more elements that are chemically bound together. Common table salt (NaCl) fits this idea: it’s made from sodium and chlorine bonded in an ionic compound. In solid form it exists as a lattice of ions rather than a single discrete molecule, which distinguishes it from a simple element and from covalently bonded molecules. Oxygen is an element, while water and glucose are covalently bonded molecules composed of more than one element; they are molecules, whereas salt is a classical example of a compound in many introductory contexts.