Build a nucleus – protons, neutrons, stability and decay

PhysicsQuantum & Nuclear PhysicsAges 17–18

Add and remove protons and neutrons with buttons to build a nucleus, then read its element symbol, mass number A = Z + N and stability. An unstable nucleus shows its half-life on a logarithmic time scale and a button for its decay mode (alpha, beta-minus, beta-plus, proton emission or neutron emission); press it to see the daughter nucleus, which may itself be unstable and decay again. The Nuclide chart screen draws an N–Z grid coloured by decay mode, with bold lines at the magic numbers 2, 8 and 20; tap a cell to select that nucleus. Adapted from the "Build a Nucleus" simulation by PhET Interactive Simulations, University of Colorado Boulder (CC BY 4.0); rewritten.

Lesson: Nuclear structure and radioactive decay