94[244]PuPlutonium
Plutonium (Pu) — element 94actinide · period 7
Plutonium is a chemical element with the symbol Pu and atomic number 94. It is an actinide in period 7 of the periodic table (the f-block), with a standard atomic mass of [244] u. At room temperature (25 °C) plutonium is a solid.
💡 Known for: Used in nuclear weapons and, as plutonium-238, to power spacecraft such as Voyager and the Curiosity rover.
# Plutonium properties
| Symbol | Pu |
|---|---|
| Atomic number | 94 |
| Atomic mass | [244] u |
| Category | actinide |
| Group | — (f-block, no group number) |
| Period | 7 |
| Block | f-block |
| Electron configuration | [Rn] 5f⁶ 7s² |
| Full configuration | 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f⁶ 6s² 6p⁶ 7s² |
| Electrons per shell | 2, 8, 18, 32, 24, 8, 2 |
| Protons / electrons | 94 / 94 |
| State at 25 °C | solid |
| Melting point | 912.5 K (639.4 °C, 1182.8 °F) |
| Boiling point | 3501 K (3227.8 °C, 5842.1 °F) |
| Density | 19.84 g/cm³ |
| Electronegativity (Pauling) | 1.28 |
| First ionization energy | 6.026 eV |
| Atomic radius | 175 pm |
| Discovered | 1940 |
# Electron configuration of plutonium
The electron configuration of plutonium is [Rn] 5f⁶ 7s², written out in full as 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f⁶ 6s² 6p⁶ 7s². Its 94 electrons fill 7 shells as 2, 8, 18, 32, 24, 8, 2, so the outermost shell holds 2 electrons.
# Related elements
NpNeptuniumprevious elementAmAmericiumnext elementAcActiniumactinideThThoriumactinidePaProtactiniumactinideUUraniumactinideCmCuriumactinideBkBerkeliumactinideCfCaliforniumactinideEsEinsteiniumactinide
# Plutonium FAQ
What is the atomic number of plutonium?
The atomic number of plutonium is 94: every plutonium atom has 94 protons in its nucleus. Its symbol is Pu.
What is the atomic mass of plutonium?
The standard atomic mass of plutonium is [244] u (the mass number of its longest-lived isotope, since it has no stable isotopes).
What is the electron configuration of plutonium?
Plutonium's electron configuration is [Rn] 5f⁶ 7s² (1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f⁶ 6s² 6p⁶ 7s²), with 2, 8, 18, 32, 24, 8, 2 electrons per shell.
Is plutonium a metal?
Yes. Plutonium is an actinide, one of the metals.
What is the melting point of plutonium?
Plutonium melts at 912.5 K (639.4 °C, 1182.8 °F) and boils at 3501 K (3227.8 °C, 5842.1 °F).
What is plutonium used for / known for?
Used in nuclear weapons and, as plutonium-238, to power spacecraft such as Voyager and the Curiosity rover.