#80 / 118
80Hg200.59
Transition Metalsliquid at STPD-block

Mercury

Group: 12•Period: 6•Standard Atomic Weight: 200.59 u
Open Full Periodic TableView Bohr Model

Why is Mercury in this position?

Understanding the scientific rationale behind Mercury's position in the periodic table:

Group Assignment
Group 12

Belongs to Group 12 because it has 2 valence electrons beyond a filled d¹⁰ shell (5d¹⁰ 6s²).

Period Assignment
Period 6

Belongs to Period 6 because its outermost electrons occupy n=6.

Orbital Block
D-block

Belongs to the d-block where the 5d series completes.

Chemical Category
Transition Metals

Classified as a transition metal / group 12 metal and the only elemental metal that is liquid at room temperature.

Atomic Structure & Bohr Shell Model

Shell Distribution: [2, 8, 18, 32, 18, 2]

Bohr Atomic Shell Model(2, 8, 18, 32, 18, 2)

Hover or tap any shell orbit ring to inspect electron counts and 2n² capacities.

80 Protons (p⁺)121 Neutrons (n⁰)
KShell K: Electron 1 of 2Shell K: Electron 2 of 2LShell L: Electron 1 of 8Shell L: Electron 2 of 8Shell L: Electron 3 of 8Shell L: Electron 4 of 8Shell L: Electron 5 of 8Shell L: Electron 6 of 8Shell L: Electron 7 of 8Shell L: Electron 8 of 8MShell M: Electron 1 of 18Shell M: Electron 2 of 18Shell M: Electron 3 of 18Shell M: Electron 4 of 18Shell M: Electron 5 of 18Shell M: Electron 6 of 18Shell M: Electron 7 of 18Shell M: Electron 8 of 18Shell M: Electron 9 of 18Shell M: Electron 10 of 18Shell M: Electron 11 of 18Shell M: Electron 12 of 18Shell M: Electron 13 of 18Shell M: Electron 14 of 18Shell M: Electron 15 of 18Shell M: Electron 16 of 18Shell M: Electron 17 of 18Shell M: Electron 18 of 18NShell N: Electron 1 of 32Shell N: Electron 2 of 32Shell N: Electron 3 of 32Shell N: Electron 4 of 32Shell N: Electron 5 of 32Shell N: Electron 6 of 32Shell N: Electron 7 of 32Shell N: Electron 8 of 32Shell N: Electron 9 of 32Shell N: Electron 10 of 32Shell N: Electron 11 of 32Shell N: Electron 12 of 32Shell N: Electron 13 of 32Shell N: Electron 14 of 32Shell N: Electron 15 of 32Shell N: Electron 16 of 32Shell N: Electron 17 of 32Shell N: Electron 18 of 32Shell N: Electron 19 of 32Shell N: Electron 20 of 32Shell N: Electron 21 of 32Shell N: Electron 22 of 32Shell N: Electron 23 of 32Shell N: Electron 24 of 32Shell N: Electron 25 of 32Shell N: Electron 26 of 32Shell N: Electron 27 of 32Shell N: Electron 28 of 32Shell N: Electron 29 of 32Shell N: Electron 30 of 32Shell N: Electron 31 of 32Shell N: Electron 32 of 32OShell O: Electron 1 of 18Shell O: Electron 2 of 18Shell O: Electron 3 of 18Shell O: Electron 4 of 18Shell O: Electron 5 of 18Shell O: Electron 6 of 18Shell O: Electron 7 of 18Shell O: Electron 8 of 18Shell O: Electron 9 of 18Shell O: Electron 10 of 18Shell O: Electron 11 of 18Shell O: Electron 12 of 18Shell O: Electron 13 of 18Shell O: Electron 14 of 18Shell O: Electron 15 of 18Shell O: Electron 16 of 18Shell O: Electron 17 of 18Shell O: Electron 18 of 18PShell P: Electron 1 of 2Shell P: Electron 2 of 2HgZ = 80

Educational Note: This Niels Bohr planetary model visually illustrates principal quantum energy shells ($n=1, 2, 3\dots$) and electron counts. In modern quantum mechanics (Schrödinger model), electrons do not orbit in fixed circular planetary tracks, but exist as 3D probability clouds (orbitals: $s, p, d, f$) governed by the Heisenberg uncertainty principle.

Electron Shell Filling Breakdown

Shell K (n=1):2 / 2 electrons (100%)
Shell L (n=2):8 / 8 electrons (100%)
Shell M (n=3):18 / 18 electrons (100%)
Shell N (n=4):32 / 32 electrons (100%)
Shell O (n=5):18 / 50 electrons (36%)
Shell P (n=6):2 / 72 electrons (3%)
Aufbau Electron Configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s²

Neutral ground state configuration. Valence electrons: 2.

Atomic & Quantum Properties

Electronegativity (Pauling)2 Pauling
1st Ionization Energy1007.1 kJ/mol
Electron Affinity0 kJ/mol
Atomic Radius (empirical)171 pm
Common Oxidation States+2, +1
Crystal StructureRhombohedral

Physical & Thermal Properties

Density at STP13.53 g/cm³
Melting Point-38.83 °C (234.32 K)
Boiling Point356.73 °C (630 K)
Magnetic OrderingDiamagnetic
Discovery YearAncient
Discovered ByKnown since antiquity (~1500 BC); found in ancient Egyptian tombs

Real-World Uses, Occurrence & Compounds

Major Industrial & Everyday Uses
  • Traditional medical thermometers, barometers, and sphygmomanometers (blood pressure cuffs)
  • Energy-efficient fluorescent lighting and mercury vapor streetlights
  • Dental amalgam tooth fillings (alloyed with silver, tin, and copper)
  • Artisanal small-scale gold mining amalgamation
Occurrence in Nature

Mined from the vivid red vermilion mineral cinnabar (mercuric sulfide / HgS).

Etymology & Name Origin

Named after the swift Roman messenger god Mercury; symbol Hg from Greek 'hydrargyrum' meaning liquid silver (quicksilver)

Important Chemical Compounds
HgS (Cinnabar / Vermilion)
Hg₂Cl₂ (Calomel)
HgCl₂ (Corrosive sublimate)
(CH₃)₂Hg (Dimethylmercury)
Interesting Chemical Facts
  • • Mercury is liquid at room temperature because relativistic effects contract the 6s orbital, holding the 6s² pair so tightly that mercury atoms act almost like inert noble gas atoms with very weak interatomic bonding.
  • • An iron anvil or solid cannonball floats effortlessly on the surface of liquid mercury due to mercury's immense density (13.5 g/cm³).
  • • The phrase 'Mad as a hatter' originated because 19th-century hat makers suffered severe mercury poisoning and tremors from using mercuric nitrate to cure felt hats.
Safety & Handling Note

Extremely toxic cumulative neurotoxin; inhaling invisible mercury vapor causes neurological damage, tremors, and cognitive decline.

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