Atomic Theory

Early Atomic Models

Hydrogen Spectroscopy

1855 - 1890

1st Periodic table (Mendeleev)

1869

Roentgen Discovers X-Rays

1895

Natural Radiation discovered (Becquerel)

1896

e/m for Cathode Rays Measured (Thomson)

1897

alpha/beta radiation

1898 - 1899

Polonium/Radium Discovered (Curie)

1898

Radioactive Decay of Elements

1903

Rutherford and Soddy

Planetary Model (Rutherford)

1906 - 1913

Thomson's Plum Pudding Model

1910

Quantum Theory/Relativity

Quantum Theory of Blackbody Radiation

1900

Planck

Photoelectric Effect Explained

1905

Einstein

Special Relativity

1905 - 1925

Bohr's Hydrogen Atom

1913 - 1924

Wave Nature of Matter

1924

DeBroglie

Wave Equation/Uncertainty Principle

1925 - 1928

Fission

Neutral Radiation from Bombardment

1930

Bothe & Becker

Mass of neutral radiation estimated

1932

I. Curie & F. Joliot

'Neutron' discovered (Chadwick)

1933

Neutron Bombardment Experiments

1939 - 1940

Chain Reaction Hypothesized

1939

'Fission' indentified

1939

Meitner & Frisch

Chain Reaction Achieved

1942

December 2, U of Chicago

TRINITY test

1945

July 16

EBR-1 Generates Electricity

1951

December

Arco, ID lit with atomic power

1955