'''Plutonium''' is a [[silver]]y radioactive metal named after the planet [[Pluto]]. It is a [[man]]-made element discovered in 1940 after uranium-238 was bombarded with [[neutron]]s in a device called a [[cyclotron]]. Plutonium-238, as well as uranium-235 and uranium-233, are among the few materials whose [[atom]]s can be split (or "fissioned") to create a nuclear explosion, which releases massive amounts of [[energy]] instantly. | '''Plutonium''' is a [[silver]]y radioactive metal named after the planet [[Pluto]]. It is a [[man]]-made element discovered in 1940 after uranium-238 was bombarded with [[neutron]]s in a device called a [[cyclotron]]. Plutonium-238, as well as uranium-235 and uranium-233, are among the few materials whose [[atom]]s can be split (or "fissioned") to create a nuclear explosion, which releases massive amounts of [[energy]] instantly. |