Study Guides/Chemistry/Which Metal Is Liquid at Room Temperature?
Study Guide · Chemistry

Metal in Liquid State at Room Temperature — Mercury and Gallium

Mercury (Hg) is the only metal that exists as a liquid at standard room temperature (25°C). Its melting point is −38.83°C, which means it is a liquid at all normal temperatures encountered on Earth's surface. Gallium (Ga) is another metal that melts just above room temperature (melting point 29.76°C) and turns liquid in a warm hand. All other metals are solid at room temperature.

Question (Click to Flip)

Which metal is in the liquid state at room temperature?

Answer

Mercury (Hg) is the only metal that exists as a liquid at room temperature. Its melting point is −38.83°C, well below room temperature (25°C). Gallium (melting point 29.76°C) melts just above room temperature but is typically solid at 25°C.

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Key Facts

Mercury (Hg) is the only metal that is liquid at room temperature.

Mercury melting point: −38.83°C — liquid at all normal Earth surface temperatures.

Mercury symbol Hg comes from Latin 'Hydrargyrum' (liquid silver).

Gallium (Ga) melts at 29.76°C — liquid in a warm hand but solid at standard room temperature (25°C).

Mercury is 13.5 times denser than water.

Mercury's low melting point is due to weak metallic bonding and relativistic effects.

Mercury is highly toxic — causes neurological damage.

Mercury forms amalgams (alloys) with many metals.

Mercury — The Liquid Metal

Mercury (Hg): • Chemical symbol: Hg (from Latin: Hydrargyrum — liquid silver) • Melting point: −38.83°C (−37.89°F) • Boiling point: 356.7°C • Density: 13,534 kg/m³ (13.5 times denser than water) • Appearance: silvery-white, shiny liquid metal • Atomic number: 80

Why mercury is a liquid:

  1. Mercury has weak metallic bonding compared to other metals — its atoms do not pack tightly.
  2. Its outermost electrons (6s²) are in a full subshell and are not readily available for metallic bonding.
  3. Relativistic effects — electrons move at relativistic speeds near the heavy Hg nucleus, causing orbital contraction that weakens bonding further.

Result: Very low melting point → liquid at room temperature.

Gallium — Near-Room-Temperature Liquid

Gallium (Ga): • Melting point: 29.76°C (just above room temperature of 25°C) • Boiling point: 2229°C • Density (liquid): 6.095 g/cm³ • Appearance: silvery-white solid at room temperature; liquid in a warm hand

Gallium is often shown as an example of a metal that melts in the palm of your hand. It is solid at standard room temperature (25°C) but liquid at body temperature (37°C).

For exam purposes: • Liquid metal at room temperature = Mercury (Hg) ← standard answer • Metal that melts just above room temperature = Gallium (Ga)

Other low-melting metals: • Caesium (Cs): 28.5°C (liquid just above room temperature) • Rubidium (Rb): 39.3°C • These are very reactive alkali metals — not typically called 'liquid at room temperature'

Properties and Uses of Mercury

Physical properties: • High density (13.5× water) • Uniform thermal expansion • Does not wet glass • Good electrical conductor

Chemical properties: • Relatively unreactive (below hydrogen in activity series) • Reacts with concentrated HNO₃: 3Hg + 8HNO₃(dilute) → 3Hg(NO₃)₂ + 2NO + 4H₂O • Forms alloys called amalgams with many metals

Uses: • Thermometers (now being phased out due to toxicity) • Barometers and manometers • Electrical switches (mercury switches) • Fluorescent lamps and street lights • Dental amalgam (Hg-Ag-Sn alloy) — being replaced

Toxicity: • Mercury is highly toxic • Vapour and compounds (especially methylmercury) cause neurological damage • Minamata disease (Japan, 1950s) — caused by mercury poisoning from industrial discharge

Questions and Answers

Which metal is in the liquid state at room temperature?+

Mercury (Hg) is the only metal that exists as a liquid at room temperature. Its melting point is −38.83°C, well below room temperature (25°C). Gallium (melting point 29.76°C) melts just above room temperature but is typically solid at 25°C.

Why is mercury a liquid at room temperature?+

Mercury is a liquid at room temperature because it has very weak metallic bonding. Its outermost electrons (6s²) are in a full subshell, contributing little to metallic bonding. Additionally, relativistic effects cause orbital contraction, further weakening interatomic forces, resulting in an unusually low melting point of −38.83°C.

What is the melting point of mercury?+

The melting point of mercury (Hg) is −38.83°C (−37.89°F). This is far below room temperature, which is why mercury remains liquid at all normal ambient temperatures encountered on Earth's surface.

What does Hg stand for?+

Hg is the chemical symbol for mercury. It comes from the Latin word 'Hydrargyrum', meaning 'water silver' or 'liquid silver', reflecting mercury's silvery appearance and liquid state at room temperature.

Is gallium also a liquid at room temperature?+

Gallium (Ga) is not a liquid at standard room temperature (25°C) — its melting point is 29.76°C. However, it melts in a warm hand (at body temperature, 37°C). For exam purposes, mercury is the standard answer for the metal that is liquid at room temperature.

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