Which observation provides evidence that mercury has a partially molten (liquid) state at room temperature?

• A. Mercury forms droplets and flows easily on surfaces at room temperature.
• B. Mercury conducts electricity better than most metals.
• C. Mercury reacts vigorously with oxygen at room temperature.
• D. Mercury is magnetic at room temperature.

Answer: (A)

Verified step by step guidance

1. Understand the physical properties of mercury at room temperature, focusing on its state of matter (solid, liquid, or gas).
2. Recall that a substance in a liquid state at room temperature can flow and form droplets due to its ability to move and rearrange its particles.
3. Analyze each observation: forming droplets and flowing easily indicates liquidity; conducting electricity relates to metallic bonding but not liquidity; reacting with oxygen is a chemical property, not physical state; magnetism is related to magnetic properties, not liquidity.
4. Identify that the observation 'Mercury forms droplets and flows easily on surfaces at room temperature' directly indicates that mercury behaves like a liquid, showing it is partially molten or liquid at room temperature.
5. Conclude that the physical behavior of forming droplets and flowing is the key evidence for mercury's liquid state at room temperature.