History of the Atomic Model

John Dalton Creates Atomic Theory

Jan 1, 1803

This is the year Atomic Theory was created by the scientist John Dalton, who discovered it after experimenting with the weights of elements. He theorised that the atom was a small indestructible ball, with different sizes and kinds composing elements such as hydrogen and oxygen.

Joseph John Thomson Discovers Electrons

Jan 1, 1897

This is the year when the scientist Joseph John Thomson discovers the existance of the electron, theorising that it was positively charged matter with electrons scattered through it.

Ernest Ruthford Discovers Electrons Are Seperate

Jan 1, 1907

This is the year in which Ernest Ruthford discovered that the electron is seperate from the nucleus of the Atom.

Niel Bohr Discovers Electrons are stable

Jan 1, 1912

This is the year in which the scientist Niel Bohr discovered that electrons are in stable positions relative to the nucleus depending on energy level.

James Chadwick Discovers Neutron

Jan 1, 1932

This is the year in which the scientist James Chadwick discovered and proved the existance of the neutron in the atom, thus completing the Atomic Model.