How is an ionic bond formed?

An ionic bond is formed when a metal atom loses one or more electrons to become a positively charged ion, known as a cation. This process occurs because metals generally have a low electronegativity and can easily lose electrons. Once the metal atom loses an electron, there is a resultant positive charge.

In contrast, a nonmetal atom, which has a higher electronegativity, tends to gain the electron lost by the metal, thereby becoming a negatively charged ion called an anion. The electrostatic attraction between the positively charged cation and negatively charged anion results in the formation of the ionic bond.

This transfer of electrons and the resulting attraction between oppositely charged ions is characteristic of ionic bonds, distinguishing them from covalent bonds, where two nonmetal atoms share electrons. The other options involving the loss of electrons by nonmetals and the transfer of protons do not accurately represent the mechanism of ionic bond formation, as ionic bonds specifically require electron transfer from metals to nonmetals.