Wikijunior:The Elements/Plutonium

What does it look, feel, taste, or smell like?
Plutonium is silver when pure and turns a yellowish color when it oxidizes. A large piece of Plutonium is warm to the touch, and even larger pieces produce enough heat to boil water. Plutonium (pronounced /pluːˈtoʊniəm/) is a radioactive, metallic and toxic chemical element. It has the symbol Pu and the atomic number 94. It is a fissile element used in most modern nuclear weapons. The most significant isotope of plutonium is 239Pu, with a half-life of 24,100 years. It can be made from natural uranium and is the most useful fissile isotope of plutonium. The most stable isotope is 244Pu, with a half-life of about 80 million years, long enough to be found in extremely small quantities in nature, making 244Pu the nucleon-richest atom that naturally occurs in the Earth's crust, albeit in small traces.

How was it discovered?
Plutonium was first made by Glenn T. Seaborg, Joseph W. Kennedy, Edward M. McMillan and Arthur C. Wahl at the University of California, Berkley in 1940. It is, therefore, an artificial element (although it IS found in extremely small quantities in nature.) It was created for use in the atomic bomb.

Where did its name come from?
Plutonium was named for the planet Pluto. There is an interesting story behind its abbreviation, though. It became Pu instead of Pl because the discoverers, knowing it to be a dangerous element, chose Pu. Have you ever heard the exclamation "P.U.!" used? Well, now you can make a connection to the world of atoms and molecules.  Did You Know?
 * One kilogram of plutonium produces 22 million kilowatt hours of heat energy.
 * Plutonium has been used to power space probes and heart pacemakers.
 * It was used aboard Apollo 14 to power seismic devices.

Where is it found?
Plutonium is usually manufactured artificially in special reactors designed and built especially for this task. Trace amounts of plutonium have also been found naturally inside some uranium ores. It's virtually nonexistent, however, in the soil.

What are its uses?
The most well known use of plutonium is in the building of nuclear weapons and power plants, using its isotope 239. It is one of the key materials that cause the nuclear explosion. Less well known, however, it has been used in many instances to build long-lasting batteries for things like space probes/satellites and heart pacemakers. The heart-pacemaker use of plutonium uses the isotope 238, just one neutron away from the deadly isotope 239. If it (naturally or artificially) gained just one neutron, the heart pacemaker would probably kill you if you used it. The use of plutonium as a power source for pacemakers has been stopped in more recent years, due to this.

Is it dangerous?
Raw plutonium is both radioactive and toxic. If it comes in contact with a person, it is likely to cause an increased chance of cancer in later years of life. If ingested or inhaled it can be toxic. When used to build weapons, plutonium is extremely dangerous. It is used in the two most powerful and deadliest weapons of all time, the atomic and hydrogen bombs.