When two atoms share a pair of electrons, the bond between them is called

• A. Ionic
• B. Hydrogen
• C. Covalent
• D. Metallic

Answer: (C)

When two atoms share a pair of electrons, the bond formed is covalent. This happens when neither atom gives up its electrons completely, so they instead share one (a single covalent bond), two (a double bond), or three pairs of electrons (a triple bond) to fill their outer shells. Covalent bonds are common between nonmetals with similar electronegativity, allowing a stable attraction that holds the atoms together, as seen in molecules like H2 or O2.

Ionic bonds, by contrast, come from transferring electrons to create oppositely charged ions that attract each other. Hydrogen bonds aren’t bonds between two atoms sharing electrons; they’re weaker attractions between a hydrogen atom and a highly electronegative atom in another molecule. Metallic bonds involve a lattice of positive ions with a "sea" of delocalized electrons.