#86 / 118
86Rn[222]
Noble Gasesgas at STPP-block

Radon

Group: 18•Period: 6•Standard Atomic Weight: [222] u
Open Full Periodic TableView Bohr Model

Why is Radon in this position?

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

Group Assignment
Group 18

Belongs to Group 18 because its valence shell is a complete octet (6s² 6p⁶).

Period Assignment
Period 6

Belongs to Period 6 because its outermost electrons occupy n=6.

Orbital Block
P-block

Belongs to the p-block because its valence subshell is a full 6p orbital.

Chemical Category
Noble Gases

Classified as a noble gas due to its closed electronic octet, despite its severe nuclear radioactivity.

Atomic Structure & Bohr Shell Model

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

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

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

86 Protons (p⁺)136 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 18Shell O: Electron 2 of 18Shell O: Electron 3 of 18Shell O: Electron 4 of 18Shell O: Electron 5 of 18Shell O: Electron 6 of 18Shell O: Electron 7 of 18Shell O: Electron 8 of 18Shell O: Electron 9 of 18Shell O: Electron 10 of 18Shell O: Electron 11 of 18Shell O: Electron 12 of 18Shell O: Electron 13 of 18Shell O: Electron 14 of 18Shell O: Electron 15 of 18Shell O: Electron 16 of 18Shell O: Electron 17 of 18Shell O: Electron 18 of 18PShell P: Electron 1 of 8Shell P: Electron 2 of 8Shell P: Electron 3 of 8Shell P: Electron 4 of 8Shell P: Electron 5 of 8Shell P: Electron 6 of 8Shell P: Electron 7 of 8Shell P: Electron 8 of 8RnZ = 86

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):18 / 50 electrons (36%)
Shell P (n=6):8 / 72 electrons (11%)
Aufbau Electron Configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s² 6p⁶

Neutral ground state configuration. Valence electrons: 8.

Atomic & Quantum Properties

Electronegativity (Pauling)2.2 Pauling
1st Ionization Energy1037 kJ/mol
Electron Affinity0 kJ/mol
Atomic Radius (empirical)120 pm
Common Oxidation States0, +2
Crystal StructureFCC

Physical & Thermal Properties

Density at STP0.00973 g/cm³
Melting Point-71 °C (202 K)
Boiling Point-61.7 °C (211.45 K)
Magnetic OrderingDiamagnetic
Discovery Year1900
Discovered ByFriedrich Ernst Dorn

Real-World Uses, Occurrence & Compounds

Major Industrial & Everyday Uses
  • Hydrological groundwater tracing and earthquake prediction fault-line monitoring
  • Historical cancer radiotherapy seed implants
  • Radiological environmental air quality testing
Occurrence in Nature

Formed continuously in subterranean soils, bedrock, and granite as a gaseous decay daughter of Radium-226 in the Uranium-238 decay chain.

Etymology & Name Origin

Derived from 'radium', because it was discovered emanating from the radioactive decay of radium

Important Chemical Compounds
RnF₂ (Radon difluoride)
Interesting Chemical Facts
  • • Radon is the second-leading cause of lung cancer worldwide after tobacco smoking, responsible for an estimated 21,000 deaths annually in the United States alone.
  • • Radon is so dense (9.73 g/L) that it accumulates in low-lying residential basements, mines, and caves.
  • • When cooled below its freezing point (-71 °C), radon glows with a brilliant yellow-orange radioluminescence as its alpha particles excite surrounding atoms.
Safety & Handling Note

Major public health radiation hazard; alpha-emitting radon decay daughters lodge in bronchial lung lining causing DNA damage.

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