americium(redirected from Americanium)
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Related to Americanium: americium
n. Symbol Am
A white metallic transuranic element of the actinide series, having isotopes with mass numbers from 232 to 247. Am-241 and Am-243 are the isotopes with the longest half-lifes (432.2 years and 7,370 years, respectively), and are alpha-ray and gamma-ray emitters used as radiation sources in research, radiography, and smoke alarms. Atomic number 95; melting point 1176°C; boiling point 2011°C; specific gravity 12; valence 3, 4, 5, 6. See Periodic Table.
(Elements & Compounds) a white metallic transuranic element artificially produced from plutonium. It is used as an alpha-particle source. Symbol: Am; atomic no: 95; half-life of most stable isotope, 243Am: 7.4 × 103 years; valency: 2,3,4,5, or 6; relative density: 13.67; melting pt: 1176°C; boiling pt: 2607°C (est)
[C20: from America (because it was discovered at Berkeley, California) + -ium]
am•er•i•ci•um(ˌæm əˈrɪʃ i əm)
a transuranic element, one of the products of high-energy helium bombardment of uranium and plutonium. Symbol: Am; at. no.: 95.
Symbol Am A synthetic, silvery-white, radioactive metallic element of the actinide series that is produced artificially by bombarding plutonium with neutrons. Americium is used as a source of alpha particles for smoke detectors and gamma rays for industrial gauges. Its most stable isotope has a half-life of 7,950 years. Atomic number 95. See Periodic Table.
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|Noun||1.||americium - a radioactive transuranic metallic element; discovered by bombarding uranium with helium atoms|