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How does sodium form an ionic bond with chlorine in sodium chloride?

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Diagram showing four types of crystal bonding: ionic bonding with sodium and chlorine ions, covalent bonding with carbon atoms sharing electrons, metallic bonding with iron ions surrounded by free electrons, and molecular bonding with hydrogen molecules held by weak electrical attraction. — chemical bonding Different types of bonding in crystals.

In sodium chloride, an ionic bond forms through the transfer of an electron from a sodium atom to a chlorine atom.12

Sodium has one electron in its outermost shell, while chlorine requires one to complete its shell. By donating this electron, sodium becomes a positively charged cation (Na⁺), and chlorine becomes a negatively charged anion (Cl⁻). Both ions attain a stable, closed outer electron shell.1

The bond is sustained by the mutual electrostatic attraction between these oppositely charged ions. While the initial ionization process requires energy, the formation of a crystalline array releases a significant amount of energy, known as lattice energy. This energy release occurs because each ion becomes surrounded by multiple neighbors of the opposite charge, resulting in a stable, low-energy solid structure.341