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Chemistry · Physics
Build a Nucleus
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Add protons and neutrons, explore nuclear stability, and observe each available type of decay.
Decay
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ProtonsZ = 0
NeutronsN = 0
p–n pairA = 0
Schematic, not to scale
The nucleus is empty
Press a highlighted decay button: watch the particle fly out and the nucleus change.
Add particles to build a nucleus.
Available decays
Decay buttons are enabled for decay families listed in the model dataset. The source groups electron capture and some compound channels into basic beta/emission families. Neutrinos and antineutrinos are not drawn. This simplified picture does not list every reaction product.
Half-life
Half-life is the time for, on average, half the nuclei in a large population to decay. An individual nucleus has no countdown clock. Stable nuclei are shown with infinity; 10²⁴ s is only the end of the displayed scale.
Explore further
- Press a highlighted decay button: watch the particle fly out and the nucleus change.
- Add or remove neutrons, then compare stability and half-life.
Model notes
- The model uses the experimental nuclide tables packaged with simulation. Not every proton–neutron combination forms a nucleus.
- Decay happens when you press a button; animation speed does not represent actual half-life. Neutrinos/antineutrinos are omitted, and some compound decay channels are grouped as in the source.
- Sizes, distances and energy levels are qualitative diagrams. The Nuclide Chart shell levels belong to nuclear protons/neutrons, not electrons.
- Decay supports 94 protons and 146 neutrons; Nuclide Chart supports 10 protons and 12 neutrons.