Atom Model Timeline

Main

Democritus of Adbera

400 BC

he believe that all matter consisted of extremely small particles that couldn't be divided.

Aristoitile

318 BC

He believed in five elements : earth, air, fire, water, and aether.

John Dalton

1830

All matter is made of atoms Atoms are indivisible and indestructible

Max Planck

1900

Max Planck developed the concept of quantum mechanics.

Joseph John Thomson

1904

suggested a model of the atom as a sphere of positive matter in which electrons are positioned by electrostatic forces

Ernest Rutherford

1911

atomic theory in which the atom has a positive nucleus by surrounded negative electrons.

Niels Bohr

1913

He completed his theory of atomic structure.

Erwin Schrödinger

1923

all atoms and molecule His work led to the atomic cloud model

Robert Millikan

1923

He discovered the mass of electron and it was zero

Werner Heisenberg

1926

Werner Heisneberg discovered the Heisenberg Uncertainty Principle

Louis de Broglie

1929

His ideas were a basis for developing the wave mechanics theory

James Chadwick

1932

He discovered the neutron.