Pu
Plutonium
Element 94 · Actinide
Plutonium (Pu)
Plutonium is a radioactive metal used in nuclear weapons and reactors. Plutonium-238 powers deep-space probes.
- Actinide
- Period 7
- f-block series
- f-block
- solid at room temperature
- ☢ Radioactive
Key properties
- Atomic mass
- [244]
- u
- Electron configuration
- [Rn] 5f6 7s2
- Melting point
- 639.9 °C
- 913 K
- Boiling point
- 3,227.9 °C
- 3,501 K
- Density
- 19.84 g/cm³
- Electronegativity
- 1.28
- Pauling
- Atomic radius
- 243 pm
- van der Waals
- 1st ionisation energy
- 6.06 eV
Compare with every element:Electronegativity chartAtomic radius chartIonisation energy chartDensity chart of the elementsMelting point chartElectron configuration chart
Did you know?
Notable facts about plutonium
- 01
Its discovery was kept secret until after World War II.
- 02
Plutonium has six different solid forms at normal pressure — more than any other element.
- 03
Voyager, Cassini and the Mars rovers Curiosity and Perseverance run on plutonium-238 heat.
Applications
What is plutonium used for?
- Nuclear reactor fuel (MOX)
- Nuclear weapons
- Radioisotope generators for spacecraft
History
Discovery & name origin
Discovered by
Glenn T. Seaborg, Arthur Wahl, Joseph W. Kennedy, Edwin McMillan
Year
Where
United States
Name origin
From Pluto, then considered the planet beyond Neptune.
Atomic structure
Atomic properties
Atomic structure
Atomic properties
- Atomic number
- 94
- Atomic mass
- [244] u
- Group
- Actinides (3)
- Period
- 7
- Block
- f-block
- Electron configuration
- [Rn] 5f6 7s2
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f6
- Electrons per shell
- 2, 8, 18, 32, 24, 8, 2
- Electronegativity (Pauling)
- 1.28
- Electron affinity
- —
- Atomic radius (van der Waals)
- 243 pm
- Stable isotopes
- None — all isotopes are radioactive
Oxidation states
Highlighted: common oxidation states (+6, +5, +4, +3).
Physical
Physical properties & colour
Physical
Physical properties & colour
- State at 20 °C
- Solid
- Melting point
- 913 K · 639.9 °C · 1,183.7 °F
- Boiling point
- 3,501 K · 3,227.9 °C · 5,842.1 °F
- Density
- 19.84 g/cm³
- Molar heat capacity
- 35.5 J/(mol·K)
- Appearance
- Silvery white, tarnishing to dark grey in air
- CPK model colour
- Copied
The CPK colour is the convention used for this element’s atoms in molecular models.
FAQ
Plutonium questions
What is Pu on the periodic table?
Pu is the symbol for plutonium, element 94 on the periodic table. It sits in period 7, in the f-block, in the actinide category, and has an atomic mass of [244].
What is the atomic number of plutonium?
Plutonium has atomic number 94, so every plutonium atom has 94 protons in its nucleus. Its symbol is Pu and its atomic mass is [244].
Who discovered plutonium?
Plutonium was discovered by Glenn T. Seaborg, Arthur Wahl, Joseph W. Kennedy and Edwin McMillan in 1940 (United States). The name comes from from Pluto, then considered the planet beyond Neptune.
What is plutonium used for?
Plutonium is used for: nuclear reactor fuel (MOX); nuclear weapons; radioisotope generators for spacecraft.
Is plutonium a metal?
Yes. Plutonium is a actinide, one of the metallic elements.
What is the electron configuration of plutonium?
The electron configuration of plutonium is [Rn] 5f6 7s2. Its 94 electrons are arranged in shells as 2, 8, 18, 32, 24, 8, 2.