ac (actinium)
1ACTINIUM — L’existence dans la pechblende de l’actinium, élément radioactif de numéro atomique 89, fut établie en 1899 par André Louis Debierne, collaborateur de Pierre et Marie Curie qui venaient, un an auparavant, de découvrir, dans ce minerai d’uranium,… …
2Actinium — (pronEng|ækˈtɪniəm) is a radioactive chemical element with the symbol Ac and atomic number 89, which was discovered in 1899, the earliest discovered of the radioactive elements.CharacteristicsActinium is a silvery, radioactive, metallic element.… …
3Actinium — Radium ← Actinium → Thorium La …
4Actinium — Ac*tin i*um, n. [Gr. ?, ?, ray.] (Chem.) A supposed metal, said by Phipson to be contained in commercial zinc; so called because certain of its compounds are darkened by exposure to light. [1913 Webster] …
5actinium — ACTÍNIUM s.n. v. actiniu. Trimis de LauraGellner, 13.09.2007. Sursa: DN …
6actinium — Symbol: Ac Atomic number: 89 Atomic weight: (227) Silvery radioactive metallic element, belongs to group 3 of the periodic table. The most stable isotope, Ac 227, has a half life of 217 years. Ac 228 (half life of 6.13 hours) also occurs in… …
7actinium — (n.) radioactive element discovered in 1899, from Gk. actin , comb. form of aktis (gen. aktinos) ray, radiance (see ACTINO (Cf. actino )) + chemical suffix ium …
8actinium — [ak tin′ē əm] n. [ModL < ACTINO + IUM] a white, radioactive, metallic chemical element, the first member of the actinide series, found in pitchblende and other minerals or formed in reactors by the neutron irradiation of radium: symbol, Ac; at …
9actinium series — natural radioactive decay series starting with uranium 235 and ending with lead 207 …
10actinium K — actinium K, the name originally given to element number 87 by its discoverer, who changed it to francium in 1947 …