Periodic Table of the Elements: PlutoniumAtomic Number:94Atomic Symbol:PuPlutoniumAtomic Weight:(244)ElectronConfiguration:2 · 8 · 1832 · 248 · 2

Pu, symbol for the element plutonium.

Hydrogen bomb or H-bomb, weapon deriving a large portion of its energy from the nuclear fusion of hydrogen isotopes. In an atomic bomb, uranium or plutonium is split into lighter elements that...

Manhattan Project, the wartime effort to design and build the first nuclear weapons (atomic bombs). With the discovery of fission in 1939, it became clear to scientists that certain radioactiv...

Richland, city (1990 pop. 32,315), Benton co., S Wash., at the confluence of the Columbia and Yakima rivers, in an irrigated farm and vineyard region; inc. 1958. It is the headquarters of the ...

Hierapolis, ancient city of Phrygia, W Asia Minor, 7 mi (11.3 km) N of Laodicea and on a plateau 500 ft (152 m) above the Lycus valley (in present-day Turkey). Devoted to the worship of Leto i...

Lanzhou or Lanchow, city (1994 est. pop. 1,295,600), capital of Gansu prov., W China, on the Huang He (Yellow River) at its confluence with the Wei. It is a rail, highway, and air hub and the ...

McMillan, Edwin Mattison, 1907–91, American physicist, b. Redondo Beach, Calif., grad. California Institute of Technology, 1928, Ph.D. Princeton, 1932. On the faculty of the Univ. of Californi...

Fermium [for Enrico Fermi], artificially produced radioactive chemical element; symbol Fm; at. no. 100; mass no. of most stable isotope 257; m.p. 1,527°C; b.p. and sp. gr. unknown; valence +2,...

Actinide series, a series of radioactive metallic elements in Group 3 of the periodic table. Members of the series are often called actinides, although actinium (at. no. 89) is not always cons...