What happens to the chlorine atom during the formation of sodium chloride?

During the formation of sodium chloride (NaCl), the chlorine atom undergoes a significant change in its electron configuration by gaining an electron. Sodium (Na), which has one electron in its outer shell, donates this electron to chlorine.

Chlorine has seven electrons in its outer shell and requires one more electron to achieve a stable octet configuration. By gaining an electron from sodium, the chlorine atom transforms into a negatively charged ion, known as a chloride ion (Cl⁻). This process of gaining an electron allows chlorine to attain a stable electronic structure similar to that of a noble gas, which is energetically favorable.

This transfer of electrons from sodium to chlorine creates oppositely charged ions (Na⁺ and Cl⁻), which then attract each other, resulting in the formation of ionic bonds and the crystallization of sodium chloride. Thus, the correct answer illustrates the behavior of chlorine in this process, highlighting its role in achieving stability through electron gain.