092Actinide · Group 3 · Period 7
Uranium
Uranium (U) is element 92, a actinide in the f-block — group 3, period 7. It is a solid at room temperature with 7 electron shells (2, 8, 18, 32, 21, 9, 2) and an atomic mass of 238.028913 u.
- Atomic mass
- 238.0 u
- Phase · STP
- solid
- Melting
- 1405 K · 1132 °C
- Boiling
- 4404 K · 4131 °C
- Electronegativity
- 1.38
- Density
- 19.1 g/cm³
Photograph — Unknown authorUnknown author, Public domain, via Wikimedia Commons
Identity
- Atomic number
- 92
- Standard atomic weight
- 238.0 u
- Category
- Actinide
- Group
- 3
- Period
- 7
- Block
- f-block
- Oxidation states
- +6, +5, +4, +3
Physical properties
- Melting point
- 1405 K · 1132 °C
- Boiling point
- 4404 K · 4131 °C
- Density
- 19.1 g/cm³
- Molar heat capacity
- 27.665 J/(mol·K)
- Atomic radius
- 240 pm
- Electron affinity
- 50.94 kJ/mol
Atomic structure
92protons
146neutrons
92electrons
2valence e⁻
- Noble-gas notation
- [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
Periodic trends
Where Uranium ranks across all 118 elements.
Ionization energies
Energy to remove each successive electron (kJ/mol).
597.61
1.4k2
Successive ionization energies (kJ/mol, log scale).
Discovery
- Discovered
- 1789
- Discovered by
- Martin Heinrich Klaproth
- Named by
- —
- Appearance
- —