Plutonium, which has a symbol of Pu, an atomic weight (or mass number) of 244, and an atomic number of 94, is a radioactive metallic element that is used in nuclear reactors and nuclear weapons. The element is one of the transuranium elements in the actinide series of the periodic table. Isotopes of plutonium were first prepared and studied by the American chemist Glenn T. Seaborg and his associates at the University of California at Berkeley in 1941. Trace amounts of the element have since been found in uranium ores, but plutonium is prepared in relatively large quantities today in nuclear reactors. Chemically, plutonium is reactive, its properties somewhat resembling those of the rare earth elements. The silvery metal, which becomes slightly yellow through oxidation caused by exposure to air, exists in six varying crystalline forms and has four different oxidation states. The metal gives off heat because of its radioactivity; 15 different isotopes of plutonium, ranging in mass number from 232 to 246, are known. Plutonium melts at about 641° C (about 1186° F), boils at about 3232° C (about 5850° F), and has a specific gravity of 19.84. Plutonium has a half-life of 24,360 years, which means it will not lose its deadly power for many generations. It is an extremely hazardous poison due to its high radioactivity and it is a carcinogen. A carcinogen is a cancer-causing agent. Plutonium, which is a man-made substance, is deadly to anyone who is exposed to it. Therefore, man has made his own deathtrap.




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