Ag Cd In Au Hg Tl -- -- -- Element Fact The liquid helium-4 possesses the most unusual physical properties that defy common sense. Below 2.2 K it becomes a superfluid that can flow, against gravity, up the wall of a container.

Mercury, Hg Atomic number: 80 Atomic mass: 200.59(2) Natural abundance: 0.08 ppm Isotopes: 196Hg (195.965815) - 0.15% 198Hg (197.966752) - 9.97% 199Hg (198.968262) - 16.87% 200Hg (199.968309) - 23.10% 201Hg (200.970285) - 13.18% 202Hg (201.970626) - 29.86% 204Hg (203.973476) - 6.87% History and Production Derived from the planet Mercury. The symbol Hg is derived from the word hydrargyrum, meaning liquid silver. The element is known to ancient. It was found in Egyptian's tombs since 1500 BC. The mercury mineral cinnabar (HgS) was used as a pigment in the ancient world while extraction of the element from cinnabar and mercury amalgamation have been known since 500 BC. Up to 1500 AD, alchemists regarded the metal as a key to the transmutation of base metals to gold (which is obviously not true!). Nowadays, mercury is still obtained from cinnabar. The ore is simply roasted and the mercury vapor is condensed. Especially rich ores are usually roasted with scrap iron or quicklime (CaO). Further purification can be achieved by distillation under pressure. It has its important use in the Castner-Kellner process for manufacturing of chlorine and sodium hydroxide. Mercury is also used in the laboratory work for making thermometers and barometers. In electrical industry, as mercury-vapor lamps, electrical swithces and AC rectifiers. Certain mercury compounds have found their uses as germicides and fungicides. Physical Data It is one of the few metals that exists as liquid in room temperatures. It is heavy, and has a silvery-white in appearance. It easily forms amalgams with other metals such as gold, silver and tin. Mercury is as abundant as silver, about 0.08 ppm, which exists mostly as cinnabar. The triple point of mercury, 38.8344°C, is a fixed point on the International Temperature Scale (ITS-90). Interatomic distance: 300.6 pm Melting point: -38.83°C Boiling point: 356.73°C Thermal conductivity/Wm-1K-1: 8.34 (27°C) Density/kgm-3: 13546 (27°C) Standard Thermodynamic Data (atomic gas) Enthalpy of formation: 61.4 kJ/mol Gibbs free energy of formation: 31.8 kJ/mol Entropy: 175.0 J/mol K Heat capacity: 20.8 J/mol K Electronic data Electronic configuration: [Xe] 4f14 5d10 6s2 Term symbol: 1S0 Electron affinity: (not stable)   Electronegativity (Pauline): 1.90 Ionization energy (first, second, third): 1007.07, 1809.68, 3299.80 kJ/mol Chemical properties

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