National League for Nursing (NLN PAX) Practice Exam

Sodium is an alkali metal located in Group 1 of the periodic table, known for its high reactivity, particularly with halogens. Among the options provided, chlorine is a halogen in Group 17. Sodium readily reacts with chlorine to form sodium chloride (table salt) through a highly exothermic reaction. This occurs because sodium has one electron in its outermost shell that it tends to lose, while chlorine has seven electrons and readily gains an electron to complete its outer shell. This transfer of electrons forms a strong ionic bond between the sodium cation (Na+) and the chloride anion (Cl-).

In contrast, boron, while it is a metalloid and can form compounds with sodium, does not react as readily as chlorine in terms of bond formation and is less reactive in general. Helium, being a noble gas with a full valence shell, is very stable and does not readily participate in chemical reactions. Potassium, although it is also an alkali metal and highly reactive, will engage in similar reactions with chlorine, but sodium specifically reacts more vigorously with halogens like chlorine due to its larger ionic radius and lower ionization energy compared to potassium, making it more eager to lose its electron. Therefore, sodium