Plutonium is a radioactive element with a density of 19.86 grams, boiling point of 5842°F, and melting point of 1182.9° F. It can exist as the core of a nuclear bomb due to its radioactive properties, but is also used to power artificial pacemakers. The document provides general information about plutonium such as its atomic weight and crystal structure, and describes its uses in nuclear weapons and medical devices.