historical development of Atomic Model

Events

John dalton

1808

John dalton created the very first atomic theory
Dalton's theory
1. Atoms are tiny invisible particles
2. Atoms of one element are all the same
3. Atoms of different elements are different
4. compounds form by combining atoms

J.J Tomson

1897
  1. He was the first scientist to show that atoms were made out of even smaller things
  2. Discovered electrons and proposed the existence of a positive charged particle (his atomic model was better known as the raisin bun model)

Ernest Rutherford

1911

Discovered protons and the nucleus and that positive charged particles are in the center and are mostly empty space

Niels Bohr

1913

Improved on the rutherfodr's model.
Proposed that electrons move around the atom in specific layers or shells.

James Chadwick

1932

discovered neutrons ( particles with no charge also found within the nucleus)

the modern model

1932 - 2017

The new atomic model has electrons moving around the nucleus in a cloud