Atomic Theory TimeLine

Significant contributions

Joseph Priestley - discovered oxygen, carbon monoxide, and nitrogen dioxide

1774

Antoine Lavoisier - law of conservation of mass; father of modern chemistry

1789

Alessandro Volta - electrochemical cell and batteries

1800

Michael Faraday - electricity and electrochemistry

1831

Louis Pasteur - pasteurization process

1862

Alfred Nobel - dynamite, Nobel prize

1863

Henri Becquerel - radioactivity

1886

Guglielmo Marconi - radio

1901

Sir Fredric Banting - isolated insulin

1922

Philo Farnsworth - TV

1926

Wallace Carothers - neoprene and nylon

1931

Marie Curie - radioactivity

1934

Leo Szilard - nuclear chain reactions and atomic bomb

1934

Kary Mullis - polymerase chain reaction

1983

Historical events

Discovery of the Americans

1492

Reformation of the Catholic Church

1527

Galileo convicted of heresy

1633

Declaration of Independence

1776

Civil War

1861

First transcontinental railroad in US

1869

Assassination of Archduke Ferdinand

1914

Bolshevik revolution

1917

Treaty of Versailles

1919

Bombing of Pearl Harbor

1941

First cellular phone

1946

Initial concept for world wide web

1969

Modern Atomic Theory

John Dalton proposed that elements consisted of atoms that were identical

1803

E. Goldstein discovered canal rays

1886

E. Goldstein discovered canal rays, which have a positive charge equal to an electron.

Rutherford discovered alpha, beta, and gamma rays in radiation

1889

J.J. Thomson determined the charge to mass ratio of electrons.

1897

Max Planck proposed the idea of quantization

1900

Albert Einstein formulates Special Theory of Relativity

1905

Millikan Oil drop experiment determined the charge and the mass of an electron

1909

H. Moseley discovered the number of protons in an element is the atomic number.

1914

Niels Bohr proposed an atomic structure theory

1922

Louis deBroglie proposed that electrons have a wave/particle duality

1923

Heisenberg Proposed Principle of Indeterminacy

1927

Schrodinger Introduced wave mechanics as a mathematical model of the atom

1930

James Chadwick Discovered the neutron

1932