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500 BCE
Democritus - Leucippus
They stated that everything in the world is composed of “atoms”, which are physically indivisible, that between other atoms there isn’t any space, which means that they are indestructible. They are always moving and that there are an infinite amount of them and from different kinds. -
John Dalton (6 sept. 1766 - 27 july, 1844)
He said that atoms cannot be divided or created, that atoms of different elements can combine to form chemical compounds, and in chemical reactions atoms can be rearranged, separated, or combined. -
Eugen Goldstein (5 sept. 1850 - 25 Dec. 1930)
While he was working on his own investigation of discharge tubes, he discovered the proton -
JJ Thomson (18 Dec. 1856 - 30 Aug. 1940)
He was credited with the identification of the electron and the discovery of the subatomic particle, which are much smaller than the atom. -
Ernest Rutherford (30 Aug. 1837 - 19 Oct. 1871)
He stated have atoms have their charge concentrated in a very small nucleus -
Niels Bohr (7 Oct. 1885 - 18 Nov. 1962)
He stated that energy levels of electrons are discrete and that they revolve in stable orbits. -
James Chadwick (20 Oct. 1891 - 24 July 1974)
In 1932, he made the discovery of the neutron.
