Mercury

Mercury is a chemical element; it has symbol Hg and atomic number 80. It is also known as quicksilver and was formerly named hydrargyrum from the Greek words hydor and argyros.
Chemical compounds of mercury have found uses in batteries, in biocides in paper industry, in paints, and on seed grain, as antiseptics in pharmaceuticals, as reagents in laboratories, and as catalysts.
Symbol: Hg
Melting point: -38.83 °C
Atomic mass: 200.59 u
Atomic number: 80
Boiling point: 356.7 °C
Discovery: Ancient Egyptians (before 1500 BCE)
Electron configuration: 4f14 5d10 6s2
Although many liquids could be used in pressure measuring devices, mercury is used because its high density requires less space. It is also a good conductor of electricity, so it is a useful component of electrical switches. Mercury is also used in dental fillings, paints, soaps, batteries, and fluorescent lighting.