Plutonium


Plutonium (IPA: ) is a radioactive, metallic chemical element. It has the symbol Pu and the atomic number 94. It is the element used in most modern nuclear weapons. The most significant isotope of plutonium is <sup>239</sup>Pu, with a half-life of 24,110 years. It can be made from natural uranium and is fissile. The most stable isotope is <sup>244</sup>Pu, with a half-life of about 80 million years, long enough to be found in extremely small quantities in nature. In fact, <sup>244</sup>Pu is the nucleon-richest atom that naturally occurs in the Earth's crust, albeit in small traces.[1]