Researched
Periodic Table of Elements
Mendeleev orders the elements by weight and properties and predicts unknown ones: the map of all chemistry.
Open in the interactive tree →With 63 elements known, Mendeleev left gaps and correctly predicted the properties of gallium (1875), scandium (1879) and germanium (1886). Moseley (1913) ordered elements by nuclear charge, and quantum mechanics later explained the periods. Today the table has 118 elements.
Prerequisites
- Electrolysis (Davy, Faraday)1807Electrolysis isolated many of the elements Mendeleev arranged
- Atomic Theory (Dalton)1808
- Spectroscopy1859Spectral analysis found new elements (caesium, rubidium, gallium) that fill the table
Unlocks
- Mass Spectrometry1919
- Quantum Chemistry & Bonding1927
- Antibiotics1928
- Chemotherapy1942
- Psychiatric drugs1952
- Photovoltaics1954
- Ultrapure Silicon & Chips1954
- Ozone hole and Montreal Protocol1987
- Lithium-Ion Battery1991
- GLP-1 weight-loss drugs2021
- AI Discovers New Materials2023
- Direct air capture plants2024
- Sodium-Ion & Solid-State Cells2025–2026
- Origin of lifeopen
- True Circular Economyopen