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technetium
(Encyclopedia)technetium tĕknēˈshēəm [key] [Gr. technetos=artificial], artificially produced radioactive chemical element; symbol Tc; at. no. 43; mass no. of most stable isotope 98; m.p. 2,200℃; b.p. 4,877...mass number
(Encyclopedia)mass number, often represented by the symbol A, the total number of nucleons (neutrons and protons) in the nucleus of an atom. All atoms of a chemical element have the same atomic number (number of pr...copernicium
(Encyclopedia)copernicium, artificially produced radioactive chemical element; symbol Cn; at. no. 112; mass number of most stable isotope 285; m.p., b.p., sp. gr., and valence unknown. Situated in Group 12 of the p...americium
(Encyclopedia)americium ămərĭˈshēəm [key], artificially produced radioactive chemical element; symbol Am; at. no. 95; mass no. of most stable isotope 243; m.p. about 1,175℃; b.p. about 2,600℃; sp. gr. 13....mendelevium
(Encyclopedia)mendelevium mĕndəlāvˈēəm [key], artificially produced radioactive chemical element; symbol Md; at. no. 101; mass no. of most stable isotope 258; m.p. 827℃; b.p. and sp. gr. unknown; valence +1...Lee, David Morris
(Encyclopedia)Lee, David Morris, 1931–, American physicist, b. Rye, N.Y., Ph.D. Yale, 1959. Lee joined the faculty at Cornell in 1959, moving to Texas A&M Univ. in 2009. He was a co-recipient, with Douglas Os...bohrium
(Encyclopedia)bohrium bôrˈēəm [key], artificially produced radioactive chemical element; symbol Bh; at. no. 107; mass number of most stable isotope 270; m.p., b.p., sp. gr., and valence unknown. Situated in Gro...francium
(Encyclopedia)francium frănˈsēəm [key] [from France], radioactive chemical element; symbol Fr; at. no. 87; mass no. of most stable isotope 223; m.p. about 27℃ (estimated); b.p. 677℃ (estimated); sp. gr. unk...Richardson, Robert Coleman
(Encyclopedia)Richardson, Robert Coleman, 1937–2013, American physicist, b. Washington, D.C. Ph.D. Duke Univ., 1966. Richardson was a professor at Cornell from 1968 until his death; he was the university's first ...hassium
(Encyclopedia)hassium hăsˈēəm, häsˈ– [key], artificially produced radioactive chemical element; symbol Hs; at. no. 108; mass number of most stable isotope 277; m.p., b.p., sp. gr., and valence unknown. Situ...Browse by Subject
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