Mercury Electron Configuration

Full electron configuration of mercury (Hg, Z=80): [Xe] 4f¹⁴ 5d¹⁰ 6s². Includes orbital diagram, shell breakdown, quantum number table, and element facts.

Z = 80 Hg Mercury

Mercury — Electron Configuration

Atomic number 80 · Post-transition metal · Period 6, Group 12 · d-block

[Xe] 4f¹⁴ 5d¹⁰ 6s² 80 electrons 2 valence e⁻ Liquid at 25 °C

Subshell Breakdown

Subshell Type Electrons Max Notation
1s s orbital, n=1 2 2 1s²
2s s orbital, n=2 2 2 2s²
2p p orbitals, n=2 6 6 2p⁶
3s s orbital, n=3 2 2 3s²
3p p orbitals, n=3 6 6 3p⁶
3d d orbitals, n=3 10 10 3d¹⁰
4s s orbital, n=4 2 2 4s²
4p p orbitals, n=4 6 6 4p⁶
4d d orbitals, n=4 10 10 4d¹⁰
4f f orbitals, n=4 14 14 4f¹⁴
5s s orbital, n=5 2 2 5s²
5p p orbitals, n=5 6 6 5p⁶
5d d orbitals, n=5 10 10 5d¹⁰
6s s orbital, n=6 2 2 6s²
Total 80

Full Configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s²

All 14 subshells written explicitly.

Noble-Gas Shorthand

[Xe] 4f¹⁴ 5d¹⁰ 6s²

[Xe] = 54-electron xenon core through 5p⁶.

Shell Fill Summary

Shell 1 (n=1) — 1s² 2 / 2 electrons (100%)
Shell 2 (n=2) — 2s² 2p⁶ 8 / 8 electrons (100%)
Shell 3 (n=3) — 3s² 3p⁶ 3d¹⁰ 18 / 18 electrons (100%)
Shell 4 (n=4) — 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 32 / 32 electrons (100%)
Shell 5 (n=5) — 5s² 5p⁶ 5d¹⁰ 18 / 50 electrons (36%)
Shell 6 (n=6) — 6s² 2 / 72 electrons (3%)

Shell 5 can hold up to 50 electrons (5s + 5p + 5d + 5f + 5g); mercury uses 18 of those slots. Shell 6 holds only 2 of its possible 72.

Why Mercury Is Liquid at Room Temperature

Mercury's 6s² electrons travel at roughly 58% of the speed of light. Relativistic effects increase their effective mass, contracting the 6s orbital and stabilizing those electrons closer to the nucleus. The contracted 6s² shell participates weakly in metallic bonding, so inter-atomic cohesion is unusually low — yielding a melting point of −38.83 °C, the only metal that is liquid under standard conditions.

Summary

Full electron configuration of mercury (Hg, Z=80): [Xe] 4f¹⁴ 5d¹⁰ 6s². Includes orbital diagram, shell breakdown, quantum number table, and element facts.

How it works

  1. The Aufbau principle fills orbitals from lowest to highest energy, modified by the (n+l) rule.
  2. Mercury's 80 electrons fill all subshells through 5d¹⁰, ending with the 6s² pair.
  3. The 4f subshell (14 electrons across 7 orbitals) is completely filled, placing mercury in the d-block beyond the lanthanides.
  4. Noble-gas notation replaces the filled xenon core with [Xe] = 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶.
  5. Relativistic contraction of the 6s orbital stabilizes it, weakening inter-atomic d-d interactions and lowering the melting point below 0 °C.
  6. The closed 6s² and 5d¹⁰ shells mean mercury behaves more like a noble metal — inert, low reactivity, and liquid at 25 °C.

Use cases

  • Quick reference for chemistry homework or exam questions on period-6 d-block elements.
  • Understand why mercury is liquid at room temperature via relativistic orbital effects.
  • Compare mercury's electron configuration with cadmium (Cd, [Kr] 4d¹⁰ 5s²) and zinc (Zn, [Ar] 3d¹⁰ 4s²).
  • Verify quantum numbers for the outermost 6s electrons.
  • Teaching aid for explaining relativistic effects in heavy-element chemistry.
  • Study the f-block insertion and its impact on period-6 configurations.

Frequently Asked Questions

Last updated: 2026-07-24 · Reviewed by Nham Vu