Periodic table › Radon
1. Identity and classification
Colorless, odorless, tasteless monatomic gas; emits characteristic vivid glow in high-voltage plasma tubes
- Name and symbol
- Radon (Radon) · Rn
- Atomic number
- 86
- Relative atomic weight / mass number
- [222]
- Group · period · block
- 18 · 6 · p
- Category
- Noble Gas
- State near room temperature
- Gas
- Stable isotopes
- No stable isotopes
- CAS number
- 10043-92-2
Square brackets [A] indicate a representative isotope mass number, not an average atomic weight. Neutron counts differ between isotopes.
2. Atomic structure and electron configuration
- Protons · electrons in a neutral atom
- 86 · 86
- Neutrons in reference isotope
- 136 (222Rn)
- Full electron configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁶- Abbreviated configuration
[Xe]6s² 4f¹⁴ 5d¹⁰ 6p⁶- Electrons per shell
- 2, 8, 18, 32, 18, 8
- Listed oxidation states
- 0
- Electronegativity
- Not established
- First ionization energy
- 1036.735 kJ/mol · 10.745 eV
- Electron affinity
- Not established
- Covalent radius
- 150 pm
- van der Waals radius
- 220 pm
Configurations of superheavy elements may include theoretical predictions. Different definitions of atomic radius are not interchangeable.
3. Physical and thermal properties
- Density
- 0.00973 g/cm³
- Melting point
- 202 K · -71.15 °C · -96.07 °F
- Boiling point
- 211.45 K · -61.7 °C · -79.06 °F
- Crystal structure
- FCC
- Specific heat
- 0.094 J/(g·K)
- Thermal conductivity
- 0.00361 W/(m·K)
- Enthalpy of fusion
- 3.247 kJ/mol
- Enthalpy of vaporization
- 18.1 kJ/mol
- Magnetic ordering
- Diamagnetic
- Mohs hardness
- Not established
- Speed of sound
- 178 m/s
Density and structure depend on temperature, pressure and allotrope. 25°C is a room-temperature reference, not STP. Unestablished values are not zero.
4. Chemical behavior and compounds
Closed valence shells explain low reactivity; xenon and krypton can form compounds under suitable conditions.
Selected compounds: Monatomic gas — no stable compounds at STP
Reaction reference
No ordinary reaction with air.
No ordinary reaction with water.
5. Isotopes
| Isotope | Status | Natural abundance | Half-life |
|---|---|---|---|
| 222Rn | Radioactive | — | 3.8235 d |
Half-life units: s seconds, m minutes, h hours, d days, Y years. A dash means no natural-abundance value is given, not zero. Listed records are selected ground states; metastable states are distinct.
6. Discovery and occurrence
- Discovery
- 1900 CE
- Scientists associated with discovery
- Ernest Rutherford, Robert B. Owens & Friedrich Ernst Dorn (1900)
- Location
- Canada / Germany
- Origin
- Trace Natural / Synthetic
- Listed crustal abundance
- Not established
Minerals and naming reference
Radioactive decay of ²²⁶Ra in granitic soils and uranium ores
Named from scientific/historical roots associated with Radon (Rn), discovered or characterized by Ernest Rutherford, Robert B. Owens & Friedrich Ernst Dorn (1900).
7. Applications
Geological fault-line & earthquake precursor monitoring, hydrological tracing of groundwater-surface water interactions
Detailed applications by field
- everyday
- Geological fault-line & earthquake precursor monitoring, hydrological tracing of groundwater-surface water interactions
- industry
- Used in noble gas processing, specialized alloys, and chemical manufacturing (Geological fault-line & earthquake precursor monitoring, hydrological tracing of groundwater-surface water interactions).
- electronics
- Applied in electronic components, semiconductors, or functional coatings where Radon's electronic structure ([Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶) provides target conductivity.
- medicine
- Restricted to controlled nuclear medicine or fundamental radiochemical research.
- energy
- Utilized in power generation, battery materials, catalysts, or nuclear technology involving Radon.
- aerospace
- High-performance materials, structural alloys, or space instrumentation utilizing Radon.
- agriculture
- Not used in agriculture due to radioactivity or heavy-metal toxicity.
- science
- Spectroscopic standard, crystallography, and quantum chemistry studies of Period 6 p-block elements.
8. Biological role and safety
Hazard depends on the isotope, chemical form, dose and exposure route.
Elemental substances, ions, compounds and radioisotopes can have different health effects. This is an educational reference; laboratory work requires the material safety data sheet and trained supervision.
Biological role reference
Classified as highly radioactive / synthetic in human and biological systems.