A molecular compound is

• A. A mixture of two or more nonmetals.
• B. A pure substance consisting of atoms that have covalent bonds, where electrons between atoms are shared. They are called molecules and are made up of all non-metal elements.
• C. A pure substance made from ions with ionic bonds.
• D. A substance formed by metallic bonding.

Answer: (B)

Molecular compounds form when nonmetal atoms share electrons through covalent bonds, producing discrete units called molecules. Because the bonding involves sharing rather than electron transfer, the substance is built from molecules and is typically composed of nonmetal elements. This distinguishes it from ionic compounds, which form by transfer of electrons to create ions held together by ionic bonds, and from metallic bonding, where electrons are delocalized in a metal lattice. A mixture of nonmetals would not have a single, uniform set of molecules, so it isn’t a molecular compound.