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Uranium

Element 92 · Actinide

Specimen

Atomic number
92
Atomic mass
238.03
State at room temperature
Solid
Melting point
1,135 °C
Boiling point
4,131 °C
Density
18.95 g/cm³
Discovered
1789

Atomic mass from IUPAC.1 Other physical data from PubChem.2

Can I eat it?

In food and water
Radioactive. All uranium is radioactive, but natural uranium in water and food harms the kidneys as a chemical. ATSDR says its health effects come from chemistry, not radiation. Soluble compounds harm at lower doses. 3

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The atom

U
ShellElectrons
1 (K) 2
2 (L) 8
3 (M) 18
4 (N) 32
5 (O) 21
6 (P) 9
7 (Q) outermost 2
Total92

Configuration [Rn] 5f³ 6d¹ 7s²

5f ↑ ↑ ↑
6d ↑
7s ↑ ↓
A shell diagram: each ring is an electron shell and each dot is one electron. The nucleus holds 92 protons. The outermost shell is shown in red. Electrons do not travel on rings: they fill orbitals, regions where an electron is likely to be found. The boxes are those orbitals for the electrons outside the Rn core, with one arrow per electron.

Related elements

Actinides
Ac Actinium Th Thorium Pa Protactinium Np Neptunium Pu Plutonium Am Americium Cm Curium Bk Berkelium Cf Californium Es Einsteinium Fm Fermium Md Mendelevium No Nobelium Lr Lawrencium

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Sources

  1. 1

    IUPAC Commission on Isotopic Abundances and Atomic Weights (CIAAW), 2024. Abridged Standard Atomic Weights 2024 .

    The atomic mass shown for the 84 elements that have a standard atomic weight.

  2. 2

    National Center for Biotechnology Information (PubChem), 2026. Periodic Table of Elements .

    Electron configuration, melting and boiling points, density and discovery year for all 118 elements.

  3. 3

    Agency for Toxic Substances and Disease Registry (ATSDR), 2013. Uranium | ToxFAQs .

    • Kidney damage has been seen in humans and animals after inhaling or ingesting uranium compounds.
    • Health effects of natural and depleted uranium are due to chemical effects and not to radiation.
    • Ingesting water-soluble uranium compounds will result in kidney effects at lower doses than following exposure to insoluble uranium compounds.
  4. 4

    National Institute of Standards and Technology (NIST), 2026. Atomic Weights and Isotopic Compositions for All Elements .

    Isotopic composition of each element; the most abundant isotope sets the neutron count in the nucleus view.