Scientific discovery timeline

Events

Democritus proposes first atomic model

400 B.C.

Dalton proposed Billiard Ball Model

1802

Thomson discovers electron

1897

Rutherford discovers radon

1899

Thomson proposes Plum Pudding Model

1904

Rutherford discovers nucleus

1911

Rutherford's nuclear model of an atom is announced

1911

Bohr proposed his model

1913

Bohr proposed his model of an atom to explain how electrons can have stable orbits around the nucleus

Rutherford discovers protons

1918

schrodinger proposes electron cloud model

1926

James Chadwick discovers neutron

January 29, 1932