Atom Builder

Interactive atom builder with two modes. Explore: add or remove protons, neutrons and electrons to build any atom, isotope or ion (up to 20 protons). See the nucleus structure, electron shells, and live readout of element, nuclide notation, isotope name, mass number, and charge. Challenge mode: build specific atoms and ions to score points. Teaches how element is determined by protons, how isotopes differ, and how ions form.