Updated on Sep 30, 2026
• NEW: atoms in 3D — a Bohr model with nucleus and shells, and every s, p, d, f orbital as a surface or an electron cloud.
• Reaction predictor and solubility checker rebuilt: real school chemistry or a clear "not supported".
• Corrected element data: electron affinity, atomic radius, isotopes.
• Worksheets: new empirical formula type; answer key on its own page.
• Ion search by formula (SO4, Fe2+), light theme fixes.
