Mercury
Definition and meaning of Mercury in chemistry.
Mercury is a chemical element with the symbol Hg and atomic number 80, historically known as quicksilver for its silvery appearance and fluid state. It is a heavy, highly toxic transition metal and holds the distinction of being the only metallic element that is liquid at standard conditions for temperature and pressure.
In more detail
Situated in group 12 of the periodic table, mercury is a relatively poor conductor of heat but a fair conductor of electricity, and it possesses an unusually low melting point due to the extreme stability of its fully filled 6s electron subshell. It rarely occurs free in nature; instead, it is primarily extracted from cinnabar, a bright red mercuric sulfide ore, by heating the mineral in a current of air and condensing the resulting metallic vapor. Mercury displays a strong tendency to form alloys, known as amalgams, with many other metals, including gold, silver, and tin, although it does not amalgamate with iron. Chemically, it exists primarily in the +1 and +2 oxidation states, forming a variety of organic and inorganic compounds that are typically highly toxic to the central nervous and endocrine systems. Because of its significant health and environmental hazards, the industrial and commercial use of mercury has been drastically curtailed globally through international agreements.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Hg |
| Atomic number | 80 |
| Atomic mass | 200.59 u |
| Category | Transition Metal |
| State at room temperature | Liquid |
| Melting point | -38.83 degrees Celsius |
| Boiling point | 356.73 degrees Celsius |
Despite widespread phase-outs, mercury is still utilized in the construction of certain specialized scientific instruments, such as barometers and manometers, because its high density allows for compact pressure measurement.
Frequently asked questions
Why is mercury a liquid at room temperature?
The relativistic contraction of its orbitals causes the outermost 6s electrons to be held very tightly by the nucleus, preventing them from being shared to form strong metallic bonds between individual mercury atoms.
How does mercury poisoning affect the human body?
Mercury exposure, particularly to organic forms like methylmercury, severely damages the central nervous system, leading to cognitive impairment, tremors, muscle weakness, and profound neurodevelopmental issues in fetuses.