Find the odd chemical item (state at room temperature): Select the metal that is liquid at room temperature.

Introduction / Context:
Elements can be classified by state of matter at standard conditions. Most metals are solid at room temperature; mercury is famously liquid, making it an immediate outlier.

Given Data / Assumptions:

• Iron: solid metal at room temperature.
• Silver: solid metal at room temperature.
• Gold: solid metal at room temperature.
• Mercury: liquid metal at room temperature.

Concept / Approach:
Compare physical state under standard conditions (approximately 25°C, 1 atm). Mercury’s unique liquidity among common metals distinguishes it categorically.

Step-by-Step Solution:

Verification / Alternative check:
Check melting points: Hg has a melting point well below room temperature, whereas Fe/Ag/Au melt far above it.

Why Other Options Are Wrong:
They share the “solid at room temperature” property.

Common Pitfalls:
Do not confuse “conductivity” (all conduct well) with state of matter; here the state is decisive.

Final Answer:
Mercury