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500
Democritus
First person to suggest that matter could not be infinitely divided.
coined the term "atomos" to describe the tiny particles that make up matter and that move through empty space. 460-370 B.C -
Aug 25, 600
aristotle
His ideas about matter took over those of Democritus.
Dissagreed with Democritus' idea that Atoms move through empty space. 384- 322 B.C -
Dalton
He took Democrittus' ideas about matter and revised them based off of his personal scientific research.
English school teacher who marks the beginning of delelopment of modern Atomic Therory. -
J.J. Thompson
(1856-1940) h ewas a physiscist. He designed a series of CRT that determined the ration of particle's charged to the mass. Thompson concluded that the mass of the particle was much less than the hydrogen. He wom a nebol prize in 1905 for the discovery of electron. -
American Physicist Robert Millikan
1868-1953.
He designed an oil drop Apparatus to determine the charge of the electron.
Determinded that the manitiude of the charge of the electron was 1.602x10-19 coulombs. -
Ernest rutherford
1871.
His theory explained that the negatively-charged electrons were held within the atom by their attration to the positively- charged neuclous.
His model demonstrates the neutral nature of matter with the balance of positive charges in the nucleus and negative charges of electrons surrounding it. -
William Crookes
He notices a green flash light between a cathrode ray tube. Later then he discovered that the radiation went in the tube and not on the Zn-S coating. This all lead to the descovery of television. -
James Chadwick
1891-1974.
Demonstrated that the nucleus had another neutral subatonic particle, the neutron.
He won the 1935 Nobel prize for his descovery of the neutron.
