Plutonium

Actinide · atomic number 94

94244PuPlutoniumSolidActinide

Plutonium is a transuranic radioactive chemical element with symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exhibits six allotropes and four oxidation states.

Properties of Plutonium

Element category	Actinide
Atomic number	94
Atomic mass	244 u
Phase at STP	Solid
Group	3
Period	7
Block	f
Electron configuration	[Rn] 5f6 7s2
Electrons per shell	2, 8, 18, 32, 24, 8, 2
Electronegativity (Pauling)	1.28
Melting point	912.5 K (639 °C)
Boiling point	3505 K (3232 °C)
Density	19.816 g/cm3
Discovered by	Glenn T. Seaborg

← Neptunium · Periodic table · Americium → Am

About the actinide group

Mostly radioactive, heavy metals — several made only in reactors — whose fission powers nuclear energy and weapons.

Data: Periodic-Table-JSON (CC BY-SA 3.0) · stored statically on our server. https://en.wikipedia.org/wiki/Plutonium

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🧪 Reactive nonmetal

11 elements: Elements that readily gain or share electrons — the building blocks of water, air, living tissue and most organic chemistry.

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6 elements: Full outer electron shells make these gases almost inert: they barely react, glow in discharge lamps and are used to create unreactive atmospheres.

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7 elements: In-between elements that behave as semiconductors: silicon, germanium and boron underpin electronics, glass and solar cells.

🧪 Lanthanide

15 elements: The rare-earth “inner transition” metals that give strong permanent magnets, screen phosphors and catalyst polish.

🧪 Actinide

15 elements: Mostly radioactive, heavy metals — several made only in reactors — whose fission powers nuclear energy and weapons.

🧪 Unknown properties

8 elements: Superheavy synthetic elements made atom-by-atom, existing for fractions of a second; their true chemistry is still unmeasured.