Mercury (symbol Hg, atomic number 80) is the only metal liquid at room temperature, long used in thermometers despite its toxicity. It is classified as a transition metal and sits in group 12, period 6 of the periodic table.
Overview
Mercury is the chemical element with atomic number 80 and the symbol Hg. With a standard atomic weight of 200.59, it is a transition metal. In the periodic table it occupies group 12 and period 6, and under standard conditions it is normally a liquid. Mercury is the only metal liquid at room temperature, long used in thermometers despite its toxicity.
Atomic structure
An atom of Mercury has 80 protons in its nucleus and, when neutral, 80 electrons arranged in the configuration [Xe] 4f14 5d10 6s2. Its standard atomic weight of 200.59 reflects the natural mix of its stable isotopes.
Discovery and place in the table
Mercury has been known since antiquity. It follows Gold (Au) and precedes Thallium (Tl) in order of atomic number.
| Atomic number | 80 |
|---|---|
| Symbol | Hg |
| Atomic mass | 200.59 |
| Category | Transition metal |
| Group | 12 |
| Period | 6 |
| Electron configuration | [Xe] 4f14 5d10 6s2 |
| Phase at STP | Liquid |
| Discovered | Antiquity |