Atomic Model Timeline

Timeline of contributions to the Atomic Model.

Main

Democritus

400 B.C.

Discovers that Atoms are impenetrable and can't be divided.

Aristotle

300 B.C.

Discovers four earthly elements:
Earth, Fire, Water, Air
Discovers one heavenly element:
Aether

John Dalton

1803 - 1808


Published a table with the atomic weights of six elements:
Hydrogen, Oxygen, Nitrogen, Carbon, Sulfur, Phosphorus. He also developed the Invisible Solid Sphere Model

J.J Tomson

1897


Discovered negatively charged "corpuscles" and created the Plum Pudding Model

Robert Andrews Millikan

1897

Discovered the charge and mass of the electron using an oil drop experiment.

Ernest Rutherford

1900


Demonstrated radioactivity was often spontaneous disintegration. He also developed the Planetary Model and the Nuclear Model.

Max Planck

1911 - 1918


Worked on the Quantum Theory

Niles Bohr

1912

Model of Atomic Structure

Louis de Brogile

1924

Internal Clock of the Electron

Erwin Schrodinger

1926

Work on quantum theory

Werner Heisenburg

1927

Published his uncertanty principle

James Chadunck

1932

He discovered neutrons