The Atomic Theory

Democritus

307

Expanded the atomic theory of Leucippus. All matter is composed of small particles, which combine to make larger objects and are invisible.

Antonie Lavoiser

Jan 1, 1765

Created a common language among scientist and gave proof for the Law of Conservation of Mass.

Law of Conservation of Mass

Jan 1, 1765

Firsted proved correct by Antione Lavoiser.

John Dalton

Jan 1, 1803

Used a number of carefully measured and observed experiments to creat laws.

Atomic Theory

Jan 1, 1803

John Dalton created a theory that matters are made of atoms that are identical atoms that cannot be destroyed or rearranged.

JJ Thomson

Jan 1, 1897

Founder of electrons and used cathode ray tubes to find the charge to mass ratio of an electron to be 1.759 * 108 g. He also discovered canal rays were related with a proton and helped with the understanding of an electron.

Cathode Ray Tubes

Jan 1, 1897

Proposed by JJ Thomson

Plum Pudding Model

Jan 1, 1904

A model of an atom proposed by John Dalton also known as the chocolate chip model.

Ernest Rutherford

Jan 1, 1909

Discovered that the center of the atom is positively charged, atoms also contain empty spaces, and figured electrons grouped around the nucleous. He also identified alpha, beta, and gamma radiation.

Robert Milikan

Jan 1, 1909

Used an oil drop experiment to determine the charge of an electron and that the charge of trhe overall atom is nuetral.

Ernest Rutherford

Dec 11, 1918

Discovered the mass of a proton and composition of electricity.

Ernest Rurtherford

Jan 1, 1919

Performed the first labortory conversion of one element to another

Erwin Schrodinger

Oct 1, 1926

Identified the location of moving particles.

James Chadwick

May 6, 1932

Discovered nuetral nuetrons.