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isotope
(Encyclopedia)CE5 Isotopes of hydrogen isotope īˈsətōp [key], in chemistry and physics, one of two or more atoms having the same atomic number but differing in atomic weight and mass number. The concept of ...radioactive isotope
(Encyclopedia)radioactive isotope or radioisotope, natural or artificially created isotope of a chemical element having an unstable nucleus that decays, emitting alpha, beta, or gamma rays until stability is reache...half-life
(Encyclopedia)half-life, measure of the average lifetime of a radioactive substance (see radioactivity) or an unstable subatomic particle. One half-life is the time required for one half of any given quantity of th...atomic mass unit
(Encyclopedia)atomic mass unit or amu, in chemistry and physics, unit defined as exactly 1⁄12 the mass of an atom of carbon-12, the isotope of carbon with six protons and six neutrons in its nucleus. One amu is e...darmstadtium
(Encyclopedia)darmstadtium, artificially produced radioactive chemical element; symbol Ds; at. no. 110; mass number of most stable isotope 281; m.p., b.p., sp. gr., and valence unknown. Situated in Group 10 of the ...roentgenium
(Encyclopedia)roentgenium, artificially produced radioactive chemical element; symbol Rg; at. no. 111; mass number of most stable isotope 280; m.p., b.p., sp. gr., and valence unknown. Situated in Group 11 of the p...flerovium
(Encyclopedia)flerovium, artificially produced radioactive chemical element; symbol Fl; at. no. 114; mass number of most stable isotope 289; m.p., b.p., sp. gr., and valence unknown. Situated in Group 14 of the per...radioisotope
(Encyclopedia)radioisotope: see radioactive isotope. ...Paneth, Friedrich Adolf
(Encyclopedia)Paneth, Friedrich Adolf frēˈdrĭkh äˈdôlf päˈnĕt [key], 1887–1958, Austrian chemist. He was educated at Vienna, Munich, and Glasgow. He held a number of teaching posts in Germany until he wa...meitnerium
(Encyclopedia)meitnerium mītnĭrˈēəm [key], artificially produced radioactive chemical element; symbol Mt; at. no. 109; mass number of most stable isotope 276; m.p., b.p., sp. gr., and valence unknown. Situated...Browse by Subject
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