ACS Chemistry Practice Exam 2025 – The All-in-One Guide to Exam Success!

When two nonmetals react, they typically form a molecular compound. These compounds are characterized by the sharing of electrons between the nonmetal atoms, leading to the creation of covalent bonds. In a molecular compound, the bonded atoms form distinct units or molecules, which are held together by covalent bonds rather than through the transfer of electrons, as in ionic compounds.

In contrast, ionic compounds form between metals and nonmetals, where electrons are transferred from the metal to the nonmetal. Metallic compounds consist of metal atoms bonded together, often in a lattice structure, with a sea of delocalized electrons. A metal-nonmetal compound, by definition, involves at least one metal, which eliminates the possibility of it being formed exclusively by nonmetals.

Thus, the formation of a molecular compound from two nonmetals arises from their tendency to share electrons and achieve stability through covalent bonding, making this the correct answer.