What distinguishes a covalent bond from an ionic bond?

A covalent bond is distinguished from an ionic bond primarily by the way electrons are handled between the two atoms involved. In a covalent bond, atoms share electrons, allowing each atom to attain a more stable electronic configuration commonly resembling that of noble gases. This sharing occurs because the atoms have similar electronegativities, which means they have a comparable ability to attract electrons.

This electron-sharing mechanism leads to the formation of a bond that holds the atoms together without the complete transfer of electrons that characterizes an ionic bond. In ionic bonds, one atom donates electrons to another, resulting in the formation of charged ions that are attracted to each other due to their opposite charges. Thus, the correct choice reflects the fundamental nature of a covalent bond, emphasizing the shared nature of the electrons rather than their transfer or gain/loss associated with ionic bonds.