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Mercury (Hg), element 80
Mercury (Hg) is the chemical element with atomic number 80: a transition metal in group 12, period 6. At 25 °C it is a liquid, with an atomic mass of 200.6 u.
Physical and chemical data
| Atomic number | 80 |
|---|---|
| Symbol | Hg |
| Atomic mass | 200.6 u |
| Density | 13.53 g/cm³ |
| Melting point | -38.83 °C (234.32 K) |
| Boiling point | 356.73 °C (629.88 K) |
| Electronegativity (Pauling) | 2 |
| Electron configuration | [Xe]6s2 4f14 5d10 |
| Atomic radius (van der Waals) | 209 pm |
| Oxidation states | +2, +1 |
| Physical state at 25 °C | liquid |
| Family | transition metal |
| Group and period | 12 / 6 |
| Discoverer and year | known since antiquity |
Humanity has lived with mercury since before chemistry existed as a science: there is no discoverer to record, only millennia of use.
Neighbours on the table
Horizontally, one proton less lands on Gold (Z=79); one more lands on Thallium (Z=81). Vertically, group 12 gathers relatives with similar behaviour: Zinc, Cadmium, Copernicium.
The story behind the name
Alchemists linked it to the fastest planet and the messenger god, for the quickness of its silvery drops; the symbol Hg comes from the Greek hydrargyrum, liquid silver, and English kept the old synonym quicksilver. It is the only metal liquid at 25 °C, known since antiquity: it has been found in Egyptian tombs, and in China the first emperor Qin Shi Huang was said to be buried among rivers of mercury, an irony for a man who drank mercury elixirs chasing immortality. The Mad Hatter of Alice is a real echo of the poisoning of hatters who used mercury nitrate on felt.
Physical and chemical data: PubChem Periodic Table (NCBI, compiling NIST and IUPAC), public domain, snapshot of 2026-07-10. Temperatures converted from kelvin; historical notes cross checked against classic chemistry references.
Last updated: · Methodology and sources