U
Uranium
Element 92 · Actinide
Uranium (U)
Uranium is a dense, weakly radioactive metal. Its fission powers nuclear reactors and the first atomic bombs.
- Actinide
- Period 7
- f-block series
- f-block
- solid at room temperature
- ☢ Radioactive
Key properties
- Atomic mass
- 238.0289
- u
- Electron configuration
- [Rn] 5f3 6d1 7s2
- Melting point
- 1,134.9 °C
- 1,408 K
- Boiling point
- 4,130.9 °C
- 4,404 K
- Density
- 18.95 g/cm³
- Electronegativity
- 1.38
- Pauling
- Atomic radius
- 240 pm
- van der Waals
- 1st ionisation energy
- 6.194 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 uranium
- 01
Henri Becquerel discovered radioactivity in 1896 using uranium salts.
- 02
One kilogram of uranium-235 can release as much energy as about 3,000 tonnes of coal.
- 03
Uranium glass glows green under ultraviolet light.
Applications
What is uranium used for?
- Nuclear power
- Naval reactors
- Radiation shielding (depleted uranium)
- Rock dating
History
Discovery & name origin
Discovered by
Year
Where
Germany
Name origin
From the planet Uranus, discovered eight years earlier.
Atomic structure
Atomic properties
Atomic structure
Atomic properties
- Atomic number
- 92
- Atomic mass
- 238.0289 u
- Group
- Actinides (3)
- Period
- 7
- Block
- f-block
- Electron configuration
- [Rn] 5f3 6d1 7s2
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f3 6d1
- Electrons per shell
- 2, 8, 18, 32, 21, 9, 2
- Electronegativity (Pauling)
- 1.38
- Electron affinity
- —
- Atomic radius (van der Waals)
- 240 pm
- Stable isotopes
- None — all isotopes are radioactive
Oxidation states
Highlighted: common oxidation states (+6, +5, +4, +3).
Successive ionisation energies
Energy to remove each electron in turn (kJ/mol). Big jumps show where a new, inner shell begins.
- 1st597.6
- 2nd1,420
Physical
Physical properties & colour
Physical
Physical properties & colour
- State at 20 °C
- Solid
- Melting point
- 1,408 K · 1,134.9 °C · 2,074.7 °F
- Boiling point
- 4,404 K · 4,130.9 °C · 7,467.5 °F
- Density
- 18.95 g/cm³
- Molar heat capacity
- 27.665 J/(mol·K)
- Appearance
- —
- CPK model colour
- Copied
The CPK colour is the convention used for this element’s atoms in molecular models.
FAQ
Uranium questions
What is U on the periodic table?
U is the symbol for uranium, element 92 on the periodic table. It sits in period 7, in the f-block, in the actinide category, and has an atomic mass of 238.0289.
What is the atomic number of uranium?
Uranium has atomic number 92, so every uranium atom has 92 protons in its nucleus. Its symbol is U and its atomic mass is 238.0289.
Who discovered uranium?
Uranium was discovered by Martin Heinrich Klaproth in 1789 (Germany). The name comes from from the planet Uranus, discovered eight years earlier.
What is uranium used for?
Uranium is used for: nuclear power; naval reactors; radiation shielding (depleted uranium); rock dating.
Is uranium a metal?
Yes. Uranium is a actinide, one of the metallic elements.
What is the electron configuration of uranium?
The electron configuration of uranium is [Rn] 5f3 6d1 7s2. Its 92 electrons are arranged in shells as 2, 8, 18, 32, 21, 9, 2.