THE DISCOVERY OF PLUTONIUM
Plutonium is a relatively new addition to the periodic table. It was first encountered during World War II. In 1940, scientists at the Berkeley Radiation Laboratory were experimenting with uranium, firing heavy hydrogen atoms at the element to see what would happen. Uranium is radioactive, and the bombardment caused it to split apart, releasing another radioactive element, neptunium. That element was unstable, and it decayed into yet another unknown radioactive element. Following the planetary theme, the scientists called it plutonium. Its potential as a nuclear weapon was immediately evident, and within two years top-secret plutonium production had started at the Metallurgical Laboratory in Chicago.