Which metal is liquid at room temperature?

• A. Mercury is liquid at room temperature.
• B. All metals are solids at room temperature.
• C. All metals have high melting points.
• D. Mercury forms cubic crystals.

Answer: (A)

The key idea here is how melting point determines a substance’s state at a given temperature. Mercury has a melting point of about -38.8°C, which is far below typical room temperatures. That means, under ordinary conditions, mercury exists as a liquid because it’s already melted long before you reach room temperature. The other statements mischaracterize metals in general: not all metals stay solid at room temperature (mercury is the notable exception), and many metals do not have high melting points (mercury itself has a very low melting point). The note about cubic crystals isn’t relevant to why mercury is liquid at room temperature and isn’t what defines its state here.