Periodic TableAll elementsUranium
No. 092
U
238.03 u
Element · Actinide

Uranium

Uranium (铀, symbol U) is chemical element number 92, an Actinide in period 7 of the periodic table, with a standard atomic weight of about 238.03. Heaviest naturally occurring element. The primary fuel of nuclear reactors and weapons.

Period 7Group —[Rn] 5f³ 6d¹ 7s²

Properties

Atomic number92
SymbolU
Atomic mass238.03 u
CategoryActinide
Period7
Group
Electron configuration[Rn] 5f³ 6d¹ 7s²
Electronegativity1.38
Covalent radius196 pm
Density18.95 g/cm³
Melting point1405.3 K
Boiling point4404 K
DiscoveryMartin Heinrich Klaproth, 1789

Overview

Heaviest naturally occurring element. The primary fuel of nuclear reactors and weapons. Uranium (symbol U) is chemical element number 92, sitting in period 7 of the periodic table and classed as an Actinide. As an actinide it is typically radioactive and closely tied to nuclear technology.

Its electron configuration is [Rn] 5f³ 6d¹ 7s², with 2 electrons in the outer shell, and an electronegativity of about 1.38 (Pauling). Around 25 °C it is usually a solid; it melts near 1405.3 K (1132.2 °C), boils near 4404 K (4130.9 °C), has a density around 18.95 g/cm³.

In industry and daily life it turns up in Nuclear and Research. It is regarded as a high-hazard element, so handle it with appropriate care. It was first described by Martin Heinrich Klaproth in 1789. See more trends in the visualization center.

Electron shells

U92

Electrons per shell: 2 · 8 · 18 · 32 · 21 · 9 · 2

Main uses

Hazard

HighRadioactive, Toxic

Compounds containing Uranium

No compounds in this knowledge base contain Uranium yet.

Data sources

Atomic mass uses IUPAC (CIAAW) standard atomic weights; the covalent radius is from Cordero et al. (2008). Verify on the RSC Periodic Table, PubChem and Wikipedia. Educational reference only.