Dmitri Mendeleev
The Periodic Table
Democritus
Naming the Atom
John Dalton
Describing the Nature of the Atom
Antoine Lavoisier
The Law of Conservation of Matter
J.J. Thomson
Discovering the Electron
Ernest Rutherford
Discovering the Nucleus and Proton
Neils Bohr
Energy Levels
James Chadwick
Discovering the Neutron
Werner Heisenberg
The Uncertainty Principle