Atomic Theory

Democritus

460

He was a philosopher. He was born in 460 B.C. and died 370 B.C.. The theory of Democritus held that everything is composed of "atoms."

Dalton

Sep 6, 1766

Dalton was a chemist. He was born September 6 ,1766 and died July 27 ,1844.

Josph J. Thompson

Dec 18, 1856

He was born December18, 1856. He died Aguast 30, 1940. In 1897, J.J. Thomson discovered the electron by experimenting with a Crookes, or cathode ray, tube. He demonstrated that cathode rays were negatively charged.

Eurnest Rutherfurd

Aug 30, 1871

He was a chemist. He was born Augest 30, 1871. He died October 30, 1937. After the war he succeeded J. J. Thomson in the Cavendish Professorship at Cambridge and again gathered a vigorous research group, including James Chadwick, the discoverer of the neutron.

Niels Bohr

Oct 7, 1885

He was a chemist. He was born Octobert 7, 1885. He died November 18, 1962. It was while conducting research for his doctoral thesis on the electron theory of metals that Bohr first came across Max Planck's early quantum theory, which described energy as tiny particles, or quanta.