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americium

(am′ər is̸h′ē əm, -is′-)

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noun

a radioactive, metallic chemical element, one of the actinides, produced by the beta decay of an isotope of plutonium: symbol, Am; at. no., 95

Origin: ModL, after Americ(a) + -ium: so named by Glenn T(heodore) Seaborg, one of its discoverers, by analogy with europium, the corresponding rare earth

See americium in American Heritage Dictionary 4

noun Symbol Am

A white metallic transuranic element of the actinide series, having isotopes with mass numbers from 237 to 246 and half-lives from 25 minutes to 7,950 years. Its longest-lived isotopes, Am 241 and Am 243, are alpha-ray emitters used as radiation sources in research. Atomic number 95; specific gravity 11.7; valence 3, 4, 5, 6. See Table at element.

Origin:

Origin: After America

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