[am-uh-rish-ee-uh
m] 
| a transuranic element, one of the products of high-energy helium bombardment of uranium and plutonium. Symbol: Am; atomic number: 95. |
| am·er·i·ci·um (ām'ə-rĭsh'ē-əm) n. 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. [After America.] |
americium am·er·i·ci·um (ām'ə-rĭsh'ē-əm)
n.
Symbol Am
A white metallic synthetic element of the actinide series; its longest-lived isotopes, Am 241 and Am 243, are used as radiation sources in research. Atomic number 95; specific gravity 13.7; valence 2, 3, 4, 5, 6.
| americium (ām'ə-rĭsh'ē-əm) Pronunciation Key
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. See Periodic Table. |