In what type of chemical bond does one atom donate an electron to another atom?

In an ionic bond, one atom donates an electron to another atom, resulting in the formation of ions. This occurs typically between metals and nonmetals, where the metal, having a lower electronegativity, loses one or more electrons, becoming a positively charged ion. The nonmetal, having a higher electronegativity, gains these electrons, becoming a negatively charged ion. The electrostatic attraction between these oppositely charged ions is what constitutes the ionic bond.

This type of bonding fundamentally differs from polar covalent bonds, where electrons are shared unequally between two atoms, resulting in a partial charge distribution, rather than the complete transfer of electrons. Nonpolar covalent bonds involve the equal sharing of electrons between two atoms of similar electronegativity, and metallic bonds are characterized by a "sea of electrons" that are shared among a lattice of metal atoms, not through the donation from one to another.