Plutonium is a chemical element with the symbol Pu and atomic number 94. It is a synthetic element and belongs to the actinide series of elements in the periodic table. Plutonium is a dense, silvery metal that can exhibit different colors, ranging from silvery-white to dull gray, depending on its oxidation state.

Key Characteristics of Plutonium:

1. Radioactivity: Plutonium is a radioactive element, and all of its isotopes are unstable. Its most important isotope, plutonium-239, has a half-life of about 24,110 years. Plutonium undergoes alpha decay, emitting alpha particles, during its radioactive decay. It is known for its ability to sustain a nuclear chain reaction.
2. Occurrence: Plutonium is not found naturally in significant quantities on Earth. It is a synthetic element produced in nuclear reactors as a byproduct of uranium-238 and through the process of neutron capture by uranium-238.
3. Chemical Properties: Plutonium is a reactive element and readily forms compounds with oxygen, halogens, and other elements. It exists in several oxidation states, with the +3, +4, +5, and +6 states being the most common. Plutonium can be pyrophoric, meaning it can spontaneously ignite in air.
4. Applications: Plutonium has primarily been used for its nuclear properties. It is a key material in the production of nuclear weapons, where it serves as fissile material in the form of plutonium-239. Plutonium-239 is also used as fuel in some types of nuclear reactors. Additionally, it has been used in certain types of space probes as a power source.
5. Biological Role: Plutonium is highly radioactive and poses a significant health hazard. It has no known biological role and is toxic to living organisms.

Plutonium’s synthetic nature, radioactivity, and potential for nuclear chain reactions make it a highly regulated and controlled material. Its applications have primarily been in nuclear weapons, energy production, and space exploration, and its handling requires strict safety protocols due to its radioactive and toxic nature.