Atomic Theory

Ancient

300

In 300 B.C Democritus called matter, atoms. Also Kanada said every atom was different. In 350 Plato said that atoms smashing into atoms could never create the world.

Plato

350

Born in 427 in Athens died in 347. He discoverd the five solids known as platonic solids.

Aristotle

350

Born in 384 in Greece died in 322. he proposed a 5th element called the aether.

Democritus

400

He was born in 460 B.C and died in 370 B.C. He was born in Greece. He said that ne atom could be split no matter what and also the size on an atom depends on the factors influencing it.

Joseph Black

Dec 17, 1752

Born in 1728 in Bordeaux France died in 1799. He discovered that plans and animals breathe carbion dioxide.

Antoine Lavoisier

Dec 17, 1760

Born in 1743 in Paris France died in 1794. Demonstrated oxygen in rusting metals and in plant and animal respiration.

1800-1875

Dec 17, 1800

1801 thomas young proposed theory of light and color. 1801 Ritter discovered ultaviolet rays .1869 Dmitri Mendeleev created periodic table

500-1800

Dec 17, 1800

1704 Isaac Newton proposed mechanical universe with small solid masses in motion. 1800 Dalton devised a system of chemical symbols.

The solid sphere model

Dec 17, 1800

Explains a lot of chemical properties such as how atoms combine to form molecules.

John Dalton

Dec 16, 1803

He was born in 1766 and died in 1844. He was born in Eaglesfield England. He created the first atomic weight chart.

Wilhelm C. Roentgen

Dec 17, 1895

Born in 1845 Lennep Germany died 1923. He discovered rays that he called X-rays.

Henri Becquerel

Dec 17, 1896

Born in 1852 in Paris France died in 1908. He discovered that rays from uranium are different from X-rays.

J.J Thompson

Dec 17, 1898

Born in 1856 in Cheetham England. died in 1940. He came up with the plum pudding modle which showed protons and electrons inside an atom.

Marie Curie

Dec 16, 1900

She was born in 1867 and died in 1934. She was born in Warsaw Poland. She discovered that the rays of uranium are constant no matter what type of uranium.

1875-1900

Dec 17, 1900

1896 marie curie discovered radioactivity.1896 Electrons were discovered.

Robert Millikan

Dec 17, 1910

Born in 1868 in Illinois USA. He discoverd the atomic structure of electricty.

Ernest Rutherford

Dec 17, 1910

Born in 1871 in Brightwater New Zealand. He discovered that atoms are mostly empty space and have a positive central core.

1900-1915

Dec 17, 1910

1910 neon lamps were created.1906 radio broadcasting

Nelis Bohr

Jul 25, 1912

Nelis Bohr was born in 1885 and died in 1962. His country of origin is in Copenhagen, Denmark. In 1912 he discovered that electrons in an atom orbit the nucleus like planets orbit a sun.

James Chadwick

Dec 13, 1919

James Chadwick was Born in 1891 and died in 1974. His country of origin is Manchester, England. In 1919 he discoverd the non charged partical called a neutron located in the nucleus.

Werner Heisenberg

Dec 16, 1925

He was born in lennep Germany in 1845 and died in 1923. In 1895 he discovered rays that he called X-rays.

Erwin Schrodinger

Dec 17, 1926

Born in 1887 in Vienna Austria died in 1961. He created an electron cloud modle that introduced the concept of sub energy levels

Robert Oppenheimer

Dec 17, 1930

Born in 1904 in New York USA died in 1967. He predicted that there were positrons.

1915-1950

Dec 17, 1930

1916 sonar was discovered. 1947 artificial intelligence was created. 1925 geiger counter was invented

1950-current

Dec 17, 1950

1951 Group pressure theory. 1952 Hydrogen bomb. 1952 Nuclear particle detector.

Plum Pudding Model

Dec 17, 2012

Atoms are solid spheres made up of a solid positive core with tiny negative particles embedded in the positive core.

Rutherford-Bohr model

Dec 17, 2012

Electrons are placed in shells.

Planetary model

Dec 17, 2012

Proves that nucleus is a positive core and electrons are outside the nucleus.