Plutonium is a radioactive chemical element with the symbol Pu and atomic number 94. Plutonium was first synthetically produced and isolated in late 1940 and early 1941 by a deuteron bombardment of uranium-238 in the 1.5-meter (60 in) cyclotron at the University of California, Berkeley.

Actinide Chemical Elements

The actinide series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium.

These fifteen actinide elements [Actinium (Ac), Thorium (Th), Protactinium (Pa), Uranium (U), Neptunium (Np), Plutonium (Pu), Americium (Am), Curium (Cm), Berkelium (Bk), Californium (Cf), Einsteinium (Es), Fermium (Fm), Mendelevium (Md), Nobelium (No), Lawrencium (Lr)], have very large atomic and ionic radii and exhibit an unusually large range of physical properties.