Which statement correctly describes the formation of ionic bonds?

• A. Two atoms share electrons equally.
• B. Ionic bonds form due to hydrogen bonding.
• C. Ionic bonds involve electron transfer between atoms with similar electronegativity.
• D. Ionic bonds form when two atoms have a large difference in electronegativity.

Answer: (D)

Ionic bonds form when there is a large difference in electronegativity between two atoms, causing one atom to transfer electrons to the other. This transfer creates oppositely charged ions: a positively charged cation and a negatively charged anion. The strong electrostatic (ionic) attraction between these ions holds the compound together. For example, sodium donates an electron to chlorine, producing Na+ and Cl−, which are attracted to each other.

Two atoms sharing electrons equally describes a nonpolar covalent bond. Hydrogen bonding is an intermolecular attraction, not the primary bond formation in ionic compounds. Electron transfer with similar electronegativity wouldn’t occur, and shared electrons with similar electronegativity differences lead to covalent bonds instead. The large electronegativity difference best accounts for the formation of ionic bonds.