Mercury (Hg)
Element 80 · Transition metal · Liquid at 25 °C · Group 12, Period 6
Mercury is the only metal that is liquid at room temperature. It filled thermometers and barometers for centuries before its toxicity retired it from most uses.
On the periodic table, mercury sits in group 12 in period 6. It is one of 38 elements classified as a transition metal, and at room temperature (25 °C) it is a liquid — one of only 2 elements that are liquid under ordinary conditions.
Transition metals occupy the wide d-block in the middle of the table. As a family they are hard, dense, high-melting metals that conduct heat and electricity well. Their partly filled d-orbitals let many of them take several oxidation states, form vividly colored compounds, and act as catalysts — which is why so much of industry, and so much of biology, runs on this block.
Properties of mercury
| Atomic number (Z) | 80 |
|---|---|
| Symbol | Hg |
| Atomic mass | 200.59 |
| Category | Transition metal |
| Group | 12 |
| Period | 6 |
| Block | d-block |
| Metal / nonmetal | Metal |
| State at 25 °C | Liquid |
| Electron configuration | [Xe] 4f14 5d10 6s2 |
| Electronegativity (Pauling) | 2 |
| Melting point | -38.83 °C (234.32 K / -37.89 °F) |
| Boiling point | 356.73 °C (629.88 K / 674.11 °F) |
| Density | 13.534 g/cm³ |
Position in the periodic table
Mercury shares group 12 with Zinc (Zn), Cadmium (Cd), Copernicium (Cn). Elements in the same group have the same number of outer electrons, so they tend to behave alike chemically — comparing them is one of the fastest ways to see periodic trends in action.
Physical properties
Mercury melts at -38.83 °C (234.32 K / -37.89 °F) and boils at 356.73 °C (629.88 K / 674.11 °F), giving it a liquid range of about 395.6 °C at standard pressure.
Its density is 13.534 g/cm³.
See also: the interactive periodic table, how to read the periodic table, periodic trends.