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Mercury  is a chemical element with the symbol Hg and atomic number *0, also known as Hydrargyrum, Hydrargyri. A heavy, silvery d-block element, mercury is the only metal that is liquid at standard conditions for temperature and pressure; the only other element that is liquid under these conditions is bromine, though metals such as caesium, gallium, and rubidium melt just above room temperature. With a freezing point of −*8.*3 °C and boiling point of **6.*3 °C, mercury has one of the narrowest ranges of its liquid state of any metal.
Mercury occurs in deposits throughout the world mostly as cinnabar (mercuric sulfide). Mercury poisoning can also result from exposure to water-soluble forms of mercury (such as mercuric chloride or methyl mercury), inhalation of mercury vapor, or eating seafood contaminated with mercury.
 
Physical properties
 
A pound coin (density ~7.6 g/cm3) floats in mercury due to the combination of the buoyant force and surface tension.
Mercury is a heavy, silvery-white metal. As compared to other metals, it is a poor conductor of heat, but a fair conductor of electricity. A complete explanation of this delves deep into the realm of quantum physics, but it can be summarized as follows: mercury has a unique electronic configuration where electrons fill up all the available 1s, 2s, 2p, 3s, 3p, 3d, 4s, 4p, 4d, 4f, 5s, 5p, 5d and 6s subshells.
The stability of the 6s shell is due to the presence of a filled 4f shell.. The absence of a filled inner f shell is the reason for the somewhat higher melting temperature of cadmium and zinc, although both these metals still melt easily and, in addition, have unusually low boiling points.
 
Chemical properties
Mercury does not react with most acids, such as dilute sulfuric acid, although oxidizing acids such as concentrated sulfuric acid and nitric acid or aqua regia dissolve it to give sulfate, nitrate, and chloride salts. Like silver, mercury reacts with atmospheric hydrogen sulfide. Mercury even reacts with solid sulfur flakes, which are used in mercury spill kits to absorb mercury vapors (spill kits also use activated carbon and powdered zinc).