ElementsWhat is mercury?
Mercury is the only metal that is liquid at room temperature. It is heavy, silvery and poisonous, and its use is being phased out in many countries under the Minamata Convention.
What is mercury used for?
Older thermometers and barometers, some lamps and switches, and dental amalgam. Many of these uses are now being replaced.
Where the name comes from
From the planet Mercury. The symbol Hg comes from hydrargyrum, Latin for 'liquid silver'.
Key facts
- Symbol
- Hg
- Atomic number
- 80
- Atomic mass
- 200.59 u
- Family
- Transition metal
- Period
- 6
- Group
- 12
- Block
- d
- State at room temperature
- Liquid
- Melting point
- -38.8 °C (234.32 K, -38 °F)
- Boiling point
- 356.7 °C (629.88 K, 674 °F)
- Density
- 13.53 g/cm³
- Electrons per shell
- 2, 8, 18, 32, 18, 2
- Electron configuration
- [Xe]6s2 4f14 5d10
- Common oxidation states
- +2, +1
- Electronegativity (Pauling)
- 2
- First ionisation energy
- 10.438 eV
- Electron affinity
- no value
- Atomic radius (van der Waals)
- 209 pm
- Discovered
- Known since ancient times
Place in the periodic table
Mercury is element number 80. It sits in period 6 (row 6) of the periodic table, in group 12 (column 12), and belongs to the d-block. Just before it comes gold (79), and just after it comes thallium (81). In the same column, cadmium is above it and copernicium is below it. Elements in one column tend to behave alike.
Family: Transition metals.
Physical properties
At room temperature mercury is a liquid. It melts at -38.8 °C and boils at 356.7 °C, so it stays liquid over a range of 396 degrees. Its density is 13.53 grams per cubic centimetre, so a one-litre block would weigh about 13.53 kilograms. By density it ranks 14th among the 96 elements with a measured value.
Inside the atom
An atom of mercury has 80 protons in its nucleus and, when neutral, 80 electrons around it. The electrons are arranged in 6 shells: 2, 8, 18, 32, 18, 2. The outermost shell holds 2 electrons. Written in full, the electron configuration is [Xe]6s2 4f14 5d10.
Its electronegativity on the Pauling scale is 2. This number shows how strongly an atom pulls shared electrons towards itself: fluorine, the strongest, is 3.98. Removing one electron from an atom takes 10.438 electronvolts (about 1,007 kilojoules per mole). One mole of mercury weighs 200.59 grams, so a single gram contains about 3.00 × 1021 atoms.
The ring picture is a simple model that only counts the electrons in each shell. Real atoms do not look like this.
Next steps
- Work out the weight of a compound that contains mercury with the molar mass calculator.
- Compare it with every other element in the sortable list.
- Test yourself with the symbol quiz.
Figures on this page are from PubChem (U.S. National Library of Medicine), as downloaded on 11 November 2026. See About and data sources.