Final answer:
NaCl (a. Sodium chloride) is the correct answer as it is formed by the ionic bonding between sodium ions (Na+) and chloride ions (Cl-), which is characteristic of ionic compounds.
Step-by-step explanation:
The correct answer to the question is a. NaCl, which is commonly known as table salt. An ionic compound is formed from the electrostatic attraction between oppositely charged ions, typically a metal cation and a non-metal anion. Sodium (Na) is a metal, and chlorine (Cl) is a nonmetal. When sodium and chlorine combine, they form sodium chloride (NaCl), where the sodium ion donates one electron to achieve a stable electron configuration and becomes positively charged (Na+), while the chlorine atom gains an electron to also achieve stability and becomes negatively charged (Cl-). This 1:1 ratio of Na+ to Cl- ions held together by ionic bonds characterizes NaCl as an ionic compound.
On the other hand, O2 is a molecule composed of two oxygen atoms bonded together covalently, K is the symbol for the element potassium which is a metal, and H2 is a diatomic hydrogen molecule with a covalent bond between the hydrogen atoms.