Decay Simulator: Radon-222
General data
| Element name | Radon |
|---|---|
| Chemical symbol | Rn |
| Atomic number Z | 86 |
| Isotope name (symbol) | Radon-222 (Rn-222) |
| Neutron number N | 136 |
| Mass number A=Z+N | 222 |
Interactive radioactive decay simulation of Radon-222: atom-by-atom decay, full decay chain, charts of nuclei count and activity.
| Half-life | 3.82146 d |
|---|
Radioactive decay series
- Radon-222 3.82146 d
- Polonium-218 3.097 min
- Lead-214 27.06 min
- Astatine-218 1.28 s · 0.022%
- Bismuth-214 19.71 min
- Thallium-210 1.30 min · 0.021%
- Polonium-214 163.48 μs
- Lead-210 22.20 a
- Bismuth-210 5.012 d
- Polonium-210 138.378 d
- Lead-206 stable
Rare branches (below 0.01%)
Rare branches are transformations that occur in fewer than 0.01% of decays, e.g. double beta decay or cluster emission. The nuclides they produce are practically absent from a sample, so they are hidden by default to keep the main path clear. In this series: branches - 4, nuclides - 6.
- Radon-218 33.75 ms · 1.1×10⁻⁵%
- Mercury-206 8.32 min · 1.9×10⁻⁶%
- Thallium-206 4.202 min · 1.3×10⁻⁴%
- Lead-209 3.235 h · 1.5×10⁻⁶%
- Bismuth-209 2.01×10¹⁹ a · 1.5×10⁻⁶%
- Thallium-205 stable · 1.5×10⁻⁶%
How to read the simulation
Grid: each pixel is one atom of the starting isotope. When an atom decays, the pixel takes the colour of the decay product - in decay series mode the product can decay further. The moment each atom decays is random, but the probability follows from the half-life, so after one T½ about half of the atoms remain, after two - about a quarter.
Chart N(t): what percentage of the sample atoms each nuclide makes up at a given moment. The line of the starting isotope falls (by half after each T½), the lines of stable products rise, and those of short-lived ones first rise, then fall.
Chart A(t): activity, i.e. the number of decays per second (becquerel, Bq). It depends on the number of atoms and on how fast they decay: for the same number of atoms, the shorter the T½, the higher the activity.
Simulation time runs faster (or slower) than real time - the time scale slider sets the multiplier. This way you can watch the decay of isotopes that live from fractions of a second to billions of years.
Well-known isotopes
- H-3 - Tritium - glowing watch hands, nuclear fusion fuel.
- C-14 - Radiocarbon dating.
- K-40 - Natural radioactivity - in bananas and in our bodies.
- Co-60 - Radiotherapy and radiation sterilization.
- I-131 - Thyroid treatment; Chernobyl fallout.
- Cs-137 - Long-lasting contamination after Chernobyl and Fukushima.
- Rn-222 - Radon in basements and mines.
- Ra-226 - The longest-lived isotope of radium - the element discovered by Marie and Pierre Curie in 1898.
- U-235 - Nuclear power plant fuel; start of the actinium series.
- U-238 - Age of the Earth; start of the uranium series.
- Pu-238 - Power source for space probes (Voyager, Curiosity rover).
- Am-241 - Ionization smoke detectors.
Data sources
- NNDC Wallet Cards 2023 - Data as of 15 October 2024 - licence: Public domain