Write about Plutonium atom.

     

Plutonium is a radioactive chemical element with the symbol Pu and atomic number 94.  It is an actinide metal of silvery-gray appearance that ternishes when exposed to air, and forms a dull coating when oxidized.  The element normally exhibits six allotropes and four oxidation states.  It reacts with carbon, halogens, nitrogen, silicon, and hydrogen.  When exposed to moist air, it forms oxides and hydrides that can expand the sample up to 70% in volume, which in turn flake off as a powder that is pyrophoric.  It is radioactive and can accumulate in bones, which makes the handling of plutonium dangerous.

     plutonium is the element with the highest atomic number to occur in nature.  Trace quantities arise in natural uranium-238 deposits when uranium-238 captures neutrons emitted by decay of other uranium-238 atoms.  Plutonium is much more common on Earth since 1945 as a product of neutron capture and beta decay, where some of the neutrons released by the fission process convert uranium-238 nuclei into plutonium-239.

     Producing plutonium in useful quantities for the first time was a major part of the Manhattan Project during World War II that developed the first atomic bombs.  The Fat Man bombs used in the Trinity nuclear test in July 1945, and in the bombing of Nagasaki in August 1945, had plutonium cores.  Human radiation experiments studying plutonium were conducted without informed consent, and several criticality accidents, some lethal, occurred after the war.  Disposal of plutonium waste from nuclear power plants and dismantled nuclear weapons built during the Cold War is a nuclear-proliferation and environmental concern.  Other sources of plutonium in the environment are fallout form numerous above-ground nuclear tests, now banned.