potassium

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• Potassium — (pronEng|pəˈtæsiəm) is a chemical element. It has the symbol K ( la. kalium, from ar. qalīy), atomic number 19, and atomic mass 39.0983. The name potassium comes from the word potash , as potassium was first isolated from potash. Potassium is a… …   Wikipedia

• POTASSIUM — Le potassium, troisième élément de ce groupe, possède les propriétés caractéristiques des métaux alcalins. Il a été découvert en 1807 par Humphry Davy lors de la réduction électrolytique de la potasse caustique fondue (KOH). Son symbole chimique… …   Encyclopédie Universelle

• Potassium — Argon ← Potassium → Calcium Na …   Wikipédia en Français

• Potassium — Po*tas si*um, n. [NL. See {Potassa}, {Potash}.] (Chem.) An Alkali element, occurring abundantly but always combined, as in the chloride, sulphate, carbonate, or silicate, in the minerals sylvite, kainite, orthoclase, muscovite, etc. Atomic weight …   The Collaborative International Dictionary of English

• Potassĭum — Potassĭum, soviel wie Kalium …   Meyers Großes Konversations-Lexikon

• potassium — Symbol: K Atomic number: 19 Atomic weight: 39.0983 Soft silvery metallic element belonging to group 1 of the periodic table (alkali metals). Occurs naturally in seawater and a many minerals. Highly reactive, chemically, it resembles sodium in its …   Elements of periodic system

• potassium — metallic element, 1807, coined by English chemist Sir Humphrey Davy (1778 1829) from Mod.L. potassa, Latinized form of POTASH (Cf. potash) (q.v.). Davy first isolated it from potash. Symbol K is from L. kalium potash, from Arabic al qaliy the… …   Etymology dictionary

• potassium — ► NOUN ▪ a soft silvery white reactive metallic element of the alkali metal group. ORIGIN from POTASH(Cf. ↑potash) …   English terms dictionary

• potassium — [pə tas′ē əm] n. [ModL: so named (1807) < potassa < Du potasch, POTASH, by Humphrey DAVY Sir Humphry, who first isolated it from potash] a soft, silver white, waxlike metallic chemical element, one of the alkali metals, that oxidizes… …   English World dictionary

• potassium — /peuh tas ee euhm/, n. Chem. a silvery white metallic element that oxidizes rapidly in the air and whose compounds are used as fertilizer and in special hard glasses. Symbol: K; at. wt.: 39.102; at. no.: 19; sp. gr.: 0.86 at 20°C. [1800 10; < NL; …   Universalium

• Potassium 40 — Le potassium 40, noté 40K, est l isotope du potassium dont le nombre de masse est égal à 40 : son noyau atomique compte 19 protons et 21 neutrons. C est un radioisotope du milieu naturel qu on trouve par exemple dans la bauxite… …   Wikipédia en Français