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92U238.03
Actinidessolid at STPF-block

Uranium

Group: f-block•Period: 7•Standard Atomic Weight: 238.03 u
Open Full Periodic TableView Bohr Model

Why is Uranium in this position?

Understanding the scientific rationale behind Uranium's position in the periodic table:

Group Assignment
Group Lanthanide / Actinide

Actinide series element filling the 5f subshell.

Period Assignment
Period 7

Belongs to Period 7 because its outermost electrons occupy n=7.

Orbital Block
F-block

Belongs to the f-block because valence electrons fill 5f orbitals (5f³ 6d¹ 7s²).

Chemical Category
Actinides

Classified as an actinide radioactive metal and premier nuclear fission fuel.

Atomic Structure & Bohr Shell Model

Shell Distribution: [2, 8, 18, 32, 21, 9, 2]

Bohr Atomic Shell Model(2, 8, 18, 32, 21, 9, 2)

Hover or tap any shell orbit ring to inspect electron counts and 2n² capacities.

92 Protons (p⁺)146 Neutrons (n⁰)
KShell K: Electron 1 of 2Shell K: Electron 2 of 2LShell L: Electron 1 of 8Shell L: Electron 2 of 8Shell L: Electron 3 of 8Shell L: Electron 4 of 8Shell L: Electron 5 of 8Shell L: Electron 6 of 8Shell L: Electron 7 of 8Shell L: Electron 8 of 8MShell M: Electron 1 of 18Shell M: Electron 2 of 18Shell M: Electron 3 of 18Shell M: Electron 4 of 18Shell M: Electron 5 of 18Shell M: Electron 6 of 18Shell M: Electron 7 of 18Shell M: Electron 8 of 18Shell M: Electron 9 of 18Shell M: Electron 10 of 18Shell M: Electron 11 of 18Shell M: Electron 12 of 18Shell M: Electron 13 of 18Shell M: Electron 14 of 18Shell M: Electron 15 of 18Shell M: Electron 16 of 18Shell M: Electron 17 of 18Shell M: Electron 18 of 18NShell N: Electron 1 of 32Shell N: Electron 2 of 32Shell N: Electron 3 of 32Shell N: Electron 4 of 32Shell N: Electron 5 of 32Shell N: Electron 6 of 32Shell N: Electron 7 of 32Shell N: Electron 8 of 32Shell N: Electron 9 of 32Shell N: Electron 10 of 32Shell N: Electron 11 of 32Shell N: Electron 12 of 32Shell N: Electron 13 of 32Shell N: Electron 14 of 32Shell N: Electron 15 of 32Shell N: Electron 16 of 32Shell N: Electron 17 of 32Shell N: Electron 18 of 32Shell N: Electron 19 of 32Shell N: Electron 20 of 32Shell N: Electron 21 of 32Shell N: Electron 22 of 32Shell N: Electron 23 of 32Shell N: Electron 24 of 32Shell N: Electron 25 of 32Shell N: Electron 26 of 32Shell N: Electron 27 of 32Shell N: Electron 28 of 32Shell N: Electron 29 of 32Shell N: Electron 30 of 32Shell N: Electron 31 of 32Shell N: Electron 32 of 32OShell O: Electron 1 of 21Shell O: Electron 2 of 21Shell O: Electron 3 of 21Shell O: Electron 4 of 21Shell O: Electron 5 of 21Shell O: Electron 6 of 21Shell O: Electron 7 of 21Shell O: Electron 8 of 21Shell O: Electron 9 of 21Shell O: Electron 10 of 21Shell O: Electron 11 of 21Shell O: Electron 12 of 21Shell O: Electron 13 of 21Shell O: Electron 14 of 21Shell O: Electron 15 of 21Shell O: Electron 16 of 21Shell O: Electron 17 of 21Shell O: Electron 18 of 21Shell O: Electron 19 of 21Shell O: Electron 20 of 21Shell O: Electron 21 of 21PShell P: Electron 1 of 9Shell P: Electron 2 of 9Shell P: Electron 3 of 9Shell P: Electron 4 of 9Shell P: Electron 5 of 9Shell P: Electron 6 of 9Shell P: Electron 7 of 9Shell P: Electron 8 of 9Shell P: Electron 9 of 9QShell Q: Electron 1 of 2Shell Q: Electron 2 of 2UZ = 92

Educational Note: This Niels Bohr planetary model visually illustrates principal quantum energy shells ($n=1, 2, 3\dots$) and electron counts. In modern quantum mechanics (Schrödinger model), electrons do not orbit in fixed circular planetary tracks, but exist as 3D probability clouds (orbitals: $s, p, d, f$) governed by the Heisenberg uncertainty principle.

Electron Shell Filling Breakdown

Shell K (n=1):2 / 2 electrons (100%)
Shell L (n=2):8 / 8 electrons (100%)
Shell M (n=3):18 / 18 electrons (100%)
Shell N (n=4):32 / 32 electrons (100%)
Shell O (n=5):21 / 50 electrons (42%)
Shell P (n=6):9 / 72 electrons (13%)
Shell Q (n=7):2 / 98 electrons (2%)
Aufbau Electron Configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f³ 6s² 6p⁶ 6d¹ 7s²

Neutral ground state configuration. Valence electrons: 6.

Atomic & Quantum Properties

Electronegativity (Pauling)1.38 Pauling
1st Ionization Energy597.6 kJ/mol
Electron Affinity-50.9 kJ/mol
Atomic Radius (empirical)196 pm
Common Oxidation States+6, +4
Crystal StructureOrthorhombic

Physical & Thermal Properties

Density at STP19.1 g/cm³
Melting Point1135 °C (1408 K)
Boiling Point4131 °C (4404 K)
Magnetic OrderingParamagnetic
Discovery Year1789
Discovered ByMartin Heinrich Klaproth

Real-World Uses, Occurrence & Compounds

Major Industrial & Everyday Uses
  • Nuclear power generation fuel pellets (UO₂ enriched to 3–5% ²³⁵U generates 10% of world electricity)
  • Depleted uranium (DU) high-density armor-piercing kinetic penetrator munitions and tank armor plating
  • Radiation shielding for high-dose gamma radiography cameras
  • Historical yellow-green fluorescent vaseline/uranium glassware
Occurrence in Nature

Mined from uraninite (pitchblende), carnotite, and coffinite ores, notably in Kazakhstan, Canada, and Australia.

Etymology & Name Origin

Named after the planet Uranus, which had been discovered eight years prior

Important Chemical Compounds
UO₂ (Uranium dioxide)
UF₆ (Uranium hexafluoride / Gas centrifuge enrichment)
U₃O₈ (Yellowcake)
Interesting Chemical Facts
  • • A single 7-gram uranium fuel pellet produces as much electrical energy as 17,000 cubic feet of natural gas, 3 barrels of oil, or 1 ton of coal.
  • • Two billion years ago in Oklo, Gabon, natural groundwater conditions created a self-sustaining natural underground nuclear fission reactor that operated for hundreds of thousands of years.
  • • Uranium glass made in the Victorian era glows under ultraviolet blacklight with a neon-lime luminescence.
Safety & Handling Note

Radioactive heavy metal that presents severe chemical nephrotoxicity (kidney damage) if ingested.

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