Atomic Theory

Democritus

400

Theorized that everything was made of atoms. And between the atoms lies empty space. Thought that atoms were indestuctible, and have been and always will be. Theorized this in 400 B.C.E.

John Dalton

Sep 6, 1803

Theorized everything was made up of extremly small praticles. Atoms of the same element, are identical in every way. Atoms cannot be subdivided, created or destroyed.

J.J Thomson

Apr 13, 1897

Discovered the electron, and the first stable Isotope. Theorized that atoms were made of a positivly charged material, and were scatterted with negitivly charged electrons.

Ernest Rutherford

Jan 1, 1911

Discovered the half life of an atom. Theorized that atoms conatined a very dense negitive charhe nucleus, orbited by small positive electrons. Theorized the of existence of neutrons.

NIels Bohr

Sep 27, 1911

Niels bohr worked with erenest rutherford, and created another model of the atom which stated that the electrons orbited the nucleus in certain paths. And discovered the wave legnths emitted from atoms.

Henry Moseley

Nov 19, 1914

Discovered an x ray machine to study the structure of an atom. He helped better identify the atomic number, to help reorginize the periodic table. He and others relized just how important the atomic number was.

James Chadwick

Feb 4, 1932

Discovered that electrons orbited the nucleus in cerian paths. Discovered mass of nuetron, and that nuetrons helped produce elements bigger than uranium. Helped create the uranium bomb.

Erwin Schrödinger

Oct 12, 1933

Discovered that electrons orbiteted the nucleus in certain paths. Theorized that electrons were both waves and particles. And charectized the diffrent valence shell that electrons existed on.