Science - The Contributions of Different Scientists to Atomic Theory

Democritus

400 BCE

the first discovery of the atom

John Dalton

1807

Found that each element consisted of its own brand of indivisible atom

JJ Thompson

1897

Discovered that atoms were made up of smaller components, which he called ‘corpuscles’ (that later became known as ‘electrons’)

Ernest Rutherford

1911

Found that the atom is mostly empty space, with nearly all of its mass concentrated in a central tiny nucleus

Niels Bohr

1913

Produced a model of the atom in which the electron was able to occupy only certain orbits around the nucleus.

James Chadwick

1932

the discovery of a neutron