a solid silvery grey radioactive transuranic element whose atoms can be split when bombarded with neutrons; found in minute quantities in uranium ores but is usually synthesized in nuclear reactors; 13 isotopes are known with the most important being plutonium 239
"The scientists carefully handled the silvery grey sample of plutonium, knowing that its atoms could be split to generate immense energy for the reactor."
The transuranic chemical element with atomic number 94 and symbol Pu: a silvery-gray fissile radioactive actinide metal that tarnishes when exposed to air.
"The laboratory technicians carefully sealed the fresh plutonium sample in an inert atmosphere because its surface would quickly tarnish upon exposure to air."
The name plutonium combines the dwarf planet Pluto with the suffix -ium to indicate it is a chemical element. It was named after the planet, following the tradition of naming heavier elements after celestial bodies.