Britannica Sources used in this answer

How does electron transfer create sodium and chlorine ions in sodium chloride?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

representations of molecular structure — molecule Several methods of representing a molecule's structure. In Lewis structures, element symbols represent atoms, and dots represent electrons surrounding them. A pair of shared electrons (covalent bond) may also be shown as a single dash. The ball-and-stick model better illustrates the spatial arrangement of the atoms. For aromatic compounds, the Kekulé structure is common, in which each bond is represented by a dash, carbon atoms are implied where two or more lines meet, and hydrogen atoms are usually omitted. Bond-line formulas, similar to the Kekulé structure, are often used for complex nonaromatic organic compounds. Sugars are often drawn as Fischer projections, in which the carbon “backbone” is drawn as a straight vertical line, with carbon atoms implied where horizontal lines intersect the vertical one.

In the formation of sodium chloride, the creation of ions occurs through the transfer of a valence electron from a sodium atom to a chlorine atom.12

Sodium has a single electron in its outermost shell, while chlorine requires one additional electron to complete its outer shell. By donating this electron, the sodium atom becomes a positively charged cation (Na⁺), and the chlorine atom becomes a negatively charged anion (Cl⁻). This process allows both atoms to attain a stable, closed outer shell configuration, often referred to as the octet rule.23

While the initial ionization requires an input of energy, the overall stability of the compound is achieved through the lattice energy released when these ions pack together into a crystalline array. In this structure, the strong electrostatic attraction between the alternating positive and negative ions results in a lower total energy than that of the individual neutral atoms, which is why the reaction releases heat.41