Page 52 - Curriculum Visions Dynamic Book

Plutonium (Pu)
Element 94.A radioactive element in the actinide series in the Periodic Table.
Amounts of more than about 300 grams are liable to explode spontaneously.
Key facts...
Name: plutonium
Symbol: Pu
Atomic number: 94
Atomic weight: 244
Position in Periodic Table: inner transition metal;
period 7 (actinide series)
State at room temperature: solid
Colour: silvery-white
Density of solid: 19.84 g/cc
Melting point: 639.4°C
Boiling point: 3,235°C
Origin of name: named after the planet Pluto Shell pattern of electrons: 2–8–18–32–24–8–2
Discovery
It was discovered in 1940 by Glenn T. Seaborg, Joseph W. Kennedy and Arthur C.Wahl at Berkeley, California, through deuteron bombardment of uranium.
A nuclear power station
Technology
It is the most important of the transuranium elements because of its use in nuclear weapons and as a source of nuclear power.The isotope 239Pu has
a half-life of more than 20,000 years.
A kilogram of this isotope can release
as much energy as about 22 million kilowatt–hours of heat from conventional power stations.A kilogram of plutonium produces an explosion equal to about 20,000 tonnes of TNT. Its long half-
life makes spent plutonium difficult to dispose of.
Geology
Traces of plutonium are found in uranium ores, but most plutonium comes from the conversion of uranium in nuclear reactors. That is brought about by the absorption of neutrons.The result is a change from uranium-238 to uranium-239, which then decays to plutonium-239.
Biology
Plutonium is not found in living things and is a very dangerous radioactive element. Plutonium is particularly dangerous because it emits radiation that is absorbed by bone marrow.
For more on plutonium, see Volume 15: Uranium and Other Radioactive Elements in the Elements set.
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