Which bond forms when atoms share electrons to complete outer electron shells?

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

Answer: (A)

Sharing electrons to fill outer electron shells creates a covalent bond. In covalent bonding, atoms share one or more pairs of electrons so that each atom effectively gains a full valence shell, achieving greater stability. The strength and character of a covalent bond depend on how many electron pairs are shared—single, double, or triple bonds—and on the atoms’ electronegativities, which determine how equally the electrons are shared. This type of bonding is common between nonmetals with similar tendencies to attract electrons, such as the bonds in H2, O2, or CH4.

Other bond types involve different mechanisms: ionic bonds form when electrons are transferred from one atom to another, creating oppositely charged ions that attract; hydrogen bonds are weaker, mainly intermolecular attractions between polar molecules; metallic bonding features a lattice of positive ions shared by a delocalized “sea” of electrons. These distinctions explain why the described bonding—sharing electrons to complete outer shells—is best labeled covalent.