Covalent bonds are formed when:

Covalent bonds are formed when:

• A. Ionic bonds occur between metals
• B. Metal and nonmetal form a bond
• C. Nonmetals share electrons
• D. Molecules are held together by ion exchange

Answer: (C)

Covalent bonds form when nonmetals share electrons. When nonmetal atoms come together, they often want to fill their valence shells but lack enough electrons to do so by transfer alone. By sharing electrons, each atom can count those shared electrons toward its octet, and the shared electron cloud creates a mutual attraction to both nuclei. That bonding picture explains why many stable molecules—like H2, O2, and CH4—are held together by covalent bonds. If electrons were merely transferred, you’d be describing ionic bonds, which form between metals and nonmetals and produce ions that attract each other rather than a shared electron pair. Saying molecules are held together by ion exchange isn’t how covalent bonds work, since covalent bonding is about sharing, not exchanging ions. While metal–nonmetal interactions are often ionic in basic teaching, the essential covalent description specifically emphasizes nonmetals sharing electrons, sometimes with unequal sharing leading to polar covalent bonds (as in HCl).

Covalent bonds form when nonmetals share electrons. When nonmetal atoms come together, they often want to fill their valence shells but lack enough electrons to do so by transfer alone. By sharing electrons, each atom can count those shared electrons toward its octet, and the shared electron cloud creates a mutual attraction to both nuclei. That bonding picture explains why many stable molecules—like H2, O2, and CH4—are held together by covalent bonds.

If electrons were merely transferred, you’d be describing ionic bonds, which form between metals and nonmetals and produce ions that attract each other rather than a shared electron pair. Saying molecules are held together by ion exchange isn’t how covalent bonds work, since covalent bonding is about sharing, not exchanging ions. While metal–nonmetal interactions are often ionic in basic teaching, the essential covalent description specifically emphasizes nonmetals sharing electrons, sometimes with unequal sharing leading to polar covalent bonds (as in HCl).