Which of the following is a non-metal that remains liquid at room temperature?

Analyze the question: You need a non-metal that is a liquid at room temperature (about 25°C).

Concept: Only two elements are liquid at room temperature and normal pressure:

• Mercury, which is a metal
• Bromine, which is a non-metal (a halogen)

Check each option:

• A. Chlorine: A greenish-yellow gas at room temperature (boiling point about -34°C). ✗
• B. Phosphorus: A solid (white or red phosphorus, melting point about 44°C for white). ✗
• C. Bromine: A reddish-brown, volatile liquid at room temperature (melting point about -7°C, boiling point about 59°C). ✓
• D. Helium: A noble gas, so a gas at room temperature. ✗

Answer: The correct option is C. Bromine.

Tip: Remember the halogens by state: F₂ and Cl₂ are gases, Br₂ is a liquid, I₂ is a solid. Think "Gases first, then Liquid, then Solid" as you move down Group 17. Also remember that the two liquid elements are mercury (metal) and bromine (non-metal). JAMB likes to ask this one often.