National League for Nursing (NLN PAX) Practice Exam

Sodium reacts most readily with chlorine because both elements are highly reactive due to their positions on the periodic table. Sodium is an alkali metal, found in Group 1, which has a single electron in its outermost shell. To achieve a stable electronic configuration, sodium readily loses this electron and becomes a positively charged ion (Na⁺).

Chlorine, on the other hand, is a halogen located in Group 17 and has seven electrons in its outer shell. It requires just one more electron to complete its octet and achieve stability. When sodium and chlorine react, sodium donates its single outer electron to chlorine, which then forms a negatively charged ion (Cl⁻). This transfer of electrons results in the formation of sodium chloride (NaCl), a stable ionic compound.

The other elements listed do not share the same reactivity with sodium. Potassium, while also a Group 1 alkali metal, is less electronegative compared to chlorine and forms bonds through similar mechanisms but not as readily as sodium with chlorine. Helium is a noble gas with a complete outer shell, making it extremely unreactive. Boron, although it can form compounds with sodium, does not react as readily as chlorine due to its position