From the course "How the periodic table was made"

Periodic Table Builder

Do each step as the chemists did. The app tells you what history found, so you rebuild the table instead of memorizing it.

Data: Lavoisier's 1789 table (33 entries); K-alpha₁ energies from the X-ray Data Booklet (LBNL), Table 1-2; atomic weights are rounded IUPAC abridged values. Years and discoverers are approximate and should be checked before quoting. Course notes live in the course folder, sessions 001 and 002.