Bohr atomic model and mini periodic table (Z = 1–20)

Integrated ScienceAtoms, Elements & BondingAges 12–13

Pick the atomic number Z with the ± buttons or by tapping a cell in the mini periodic table. The simulation draws a nucleus of protons and neutrons with electrons orbiting in shells following the Bohr model (shell 1 holds up to 2e, shell 2 up to 8e, shell 3 up to 8e). Students see that protons = electrons = Z, atomic mass ≈ protons + neutrons (amu), the number of shells equals the period number, the number of outer-shell electrons equals the group A number, and the matching cell/period/group is highlighted on the table.