Final answer:
Sodium (Na) forms a cation in the composition of sodium chloride (NaCl), where it pairs with a chloride anion to form a stable ionic compound with a 1:1 ratio of sodium cations to chloride anions.
Step-by-step explanation:
NaCl is composed of two elements: sodium and chlorine. Sodium (Na) forms a cation, which is a positively charged ion. In the formation of sodium chloride (NaCl), sodium atoms lose one electron to form Na+ ions, hence becoming cations.
Chlorine atoms, on the other hand, gain an electron to form chloride anions, Cl−. The ionic compound sodium chloride is composed of these sodium cations and chloride anions in a 1:1 ratio, creating a crystalline solid where each sodium ion is surrounded by six chloride ions and each chloride ion is surrounded by six sodium ions.