Which of the following diatomic species is best classified as an ionic compound?

• A. N2
• B. NaCl
• C. O2
• D. HCl

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the difference between ionic and covalent bonds. Ionic compounds form when electrons are transferred from a metal to a nonmetal, resulting in positively and negatively charged ions held together by electrostatic forces. Covalent compounds form when atoms share electrons, typically between nonmetals.
2. Step 2: Identify the elements in each diatomic species and classify them as metals or nonmetals. For example, NaCl consists of sodium (Na), a metal, and chlorine (Cl), a nonmetal, which suggests ionic bonding.
3. Step 3: Analyze the other species: N2, O2, and HCl. N2 and O2 are composed of two nonmetals of the same element, so they form nonpolar covalent bonds. HCl is formed between two nonmetals (hydrogen and chlorine), so it is a polar covalent molecule, not ionic.
4. Step 4: Conclude that NaCl is the only species among the options that is an ionic compound because it consists of a metal and a nonmetal with electron transfer forming ions.
5. Step 5: Summarize that the best classification of an ionic compound among the given options is NaCl, while the others are covalent molecules.