Physics - Modern Physics - Atomic Structure - Structure of the atom - Atom Builder

An interactive atom model. Students add protons (red, +), neutrons (blue, 0) to the nucleus, and electrons (green, -) to shells around it. Display: atomic number (Z = protons), mass number (A = protons + neutrons), charge (protons - electrons). Build specific atoms: Hydrogen (1p, 0n, 1e), Helium (2p