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.

Use the Mercury Electron Configuration

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

Mercury (Hg) has atomic number 80 and the ground-state electron configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s², condensed as [Xe] 4f¹⁴ 5d¹⁰ 6s². The completely filled 5d and 6s subshells produce unusually weak metallic bonding — the direct reason mercury is liquid at room temperature. This tool displays the full orbital diagram, subshell breakdown, shell-fill summary, quantum numbers for the outermost shell, and key physical and chemical facts.

How it works

  1. The Aufbau principle fills orbitals from lowest to highest energy, modified by the (n+l) rule.
  2. Under the Madelung (n+l) rule, the 6s subshell fills before 4f and 5d; completing 5d¹⁰ yields the ground state, written [Xe] 4f¹⁴ 5d¹⁰ 6s².
  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 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: 2026-06-19 · Reviewed by Nham Vu