Rn
222.000Radon
Radon
Radon is a radioactive noble gas with atomic number 86. It forms from uranium and radium decay, accumulates in buildings, emits alpha radiation and is a major lung cancer risk after smoking.
86
222 g/mol
[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶
2 | 8 | 18 | 32 | 18 | 8
—
9.73e-3 g/cm³
-71.15 °C
-61.65 °C
Friedrich Ernst Dorn
Radon was discovered in 1900 by Friedrich Ernst Dorn as a radioactive gas released from radium compounds. It was once called radium emanation before the name radon was adopted.
Radon-219
Half-life: About 4 seconds. Actinium-series isotope, sometimes called actinon.Radon-220
Half-life: About 56 seconds. Thorium-series isotope, historically called thoron.Radon-222
Half-life: About 3.8 days. Most important environmental radon isotope from radium-226 decay.RnF₂
Radon DifluorideUnstable noble-gas compound studied in heavy noble gas chemistry.- Radon testing and mitigation in homes and buildings
- Geological and groundwater tracing research
- Historical radon seed radiotherapy, now replaced by better-controlled sources
- Earthquake and soil-gas research, although not a reliable prediction method
Radon has no biological role. Radon-222 and its short-lived decay products can be inhaled, deposit in the lungs and increase lung cancer risk through alpha radiation.
- Radon is colorless and odorless, so testing is needed to know whether indoor levels are elevated.
- Radon is often cited as the second leading cause of lung cancer after smoking.
- Radon-222 comes from uranium decay through radium-226 in rocks and soils.
- Although radon is a noble gas, heavy noble gas chemistry allows compounds such as radon difluoride under special conditions.
- Radon has atomic number 86 and symbol Rn.
- Its electron configuration is [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶.
- Radon is a radioactive noble gas.
- Remember Rn-222 for indoor air risk and uranium-radium decay chains.
What is the atomic number of radon?
The atomic number of radon is 86.
What is the electron configuration of radon?
Radon has the electron configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶.
What is radon used for?
Radon has limited modern uses; it is mainly important for testing, mitigation, environmental tracing and historical radiotherapy context.
Why is radon dangerous?
Radon decay products can be inhaled and irradiate lung tissue with alpha particles, increasing lung cancer risk.
What is radon-222?
Radon-222 is the main environmental radon isotope, with a half-life of about 3.8 days, formed from radium-226 decay.
Is radon a noble gas?
Yes. Radon is a group 18 noble gas, but all of its isotopes are radioactive.