americium

am·er·i·ci·um

A0252600 (ăm′ə-rĭsh′ē-əm)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.

---

[After America.]

americium

(ˌæməˈrɪsɪəm) n (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)

n. a transuranic element, one of the products of high-energy helium bombardment of uranium and plutonium. Symbol: Am; at. no.: 95. [1946; Americ(a) + -ium²]

am·er·i·ci·um

(ăm′ə-rĭsh′ē-əm) 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.

Thesaurus

Noun

1.

americium - a radioactive transuranic metallic element; discovered by bombarding uranium with helium atomsAm, atomic number 95metal, metallic element - any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc.

Translations