americium

American  

[am-uh-rish-ee-uhm] / ˌæm əˈrɪʃ i əm /

noun

Chemistry.

1. a transuranic element, one of the products of high-energy helium bombardment of uranium and plutonium. Am; 95.

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americium British  

/ ˌæməˈrɪsɪəm /

noun

1. 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, ²⁴³ Am: 7.4 × 10³ years; valency: 2,3,4,5, or 6; relative density: 13.67; melting pt: 1176°C; boiling pt: 2607°C (est)

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americium Scientific  

/ ăm′ə-rĭsh′ē-əm /

1. 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; specific gravity 11.7; valence 3, 4, 5, 6.

2. See Periodic Table

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Etymology

Origin of americium

An Americanism dating back to 1945–50; Americ(a) + -ium

Example Sentences

In 2006, when the facility was operated by a different owner, three workers received emergency chemical treatment after inhaling Americium 241 at levels above the regulatory limits.

From Seattle Times • Nov. 25, 2020

Americium emits almost exclusively alpha particles, the nuclei of helium atoms produced by the isotope's slow decay into lighter elements.

From Time Magazine Archive