Correct Property and Reason for Group VII Halogens

Steps:

• Identify Group VII as halogens, non-metals with 7 valence electrons forming diatomic molecules.
• Evaluate each option: check if the stated property is accurate and if the reason logically explains it.
• Eliminate options with factual errors in property or mismatched reason.
• Confirm the option where both property and reason align with halogen chemistry.

Why A is correct:

• Halogens have 7 outer electrons, so they share one pair to form diatomic molecules (e.g., Cl₂), achieving stable octet configuration.

Why the others are wrong:

• B: Halogens are non-metals, not metals, and lack metallic shine.
• C: Iodine is less reactive than bromine, so it cannot displace bromide ions (reverse of reactivity trend).
• D: Property and reason are identical and incomplete; descending the group increases bond strength, but this does not explain a specific property.

Final answer: A