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Democritus
The mentor of Democritus, Leucippus, started the atomic theory and Democritus adapted it. Democritus said all motions are a result of active and passive affection. He developed the law of necessity. Democritus didn't have any experiments, but he discovered the atomos between 460-370 BC. -
John Dalton
He created daltons law in 1800s when he studied the chemical makeup of air and said it wasn't a solvent it was composed of small particles. He created the law of partial pressures in 1803
He created the Law of thermal expansion in the early 1800's.
He made a Chart of atomic weights in 1803. He made a new system of chemical philosophy in 1808 -
J.J Thomson
In 1897 he discovered the electron. In 1912 he discovered neon was composed of two different kinds of atoms and proved existence of isotopes. His experiments included the 1894 cathode rays experiment, in which they passed rays throughout a vacuum. In 1906 positively charges ions. All matter made up of tiny particles (corpuscles) now called electrons. -
Ernest Rutherford
In 1898 he discovered alpha and beta particles. In 1903 he created the theory of radioactivity. In 1909 discovered the nucleus using the Gold Foil Experiment. In 1911 the Rutherford model of atom was created. In 1919 he discovered how to artificially induce a nuclear reaction into a stable element. His experiments included 1895 radio waves, x-rays with JJ Thomson, uranium which he labeled two radiation types alpha an beta, and the Gold foil experiment in which he shot alpha particles at foil. -
Niels Bohr
In 1913 he created the Bohr model. He experimented with the concept of fission. He established CERN 1954, and atoms for peace in 1955. He said electrons are restricted to particular circular orbits ,but they can move from low to high energy. He wrote quantum papers in 1913.
