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Democritus
Their speculation on atoms, taken from Leucippus, bears a passing and partial resemblance to the nineteenth-century understanding of atomic structure that has led some to regard Democritus as more of a scientist than other Greek philosophers -
John Dalton
studied and expanded upon this previous work and developed the law of multiple proportions: if two elements came together to form more than one compound, then the ratios of the masses of the second element which combine with a fixed mass of the first element will be ratios of small integers. -
James Chadwick
Chadwick’s discovery of the neutron also made it possible to produce elements heavier than uranium in the laboratory, by the capture of slow neutrons followed by beta decay. -
J.J Thompson
His work put forward a new theory, that atom was made up of small particles.Thus he discovered the electrons. -
Hantaro Nagaoka
He proposed an alternative model in which a positively charged center is surrounded by a number of revolving electrons, in the manner of Saturn and its rings. -
Earnest Rutherford
Proved that radioactivity involved the transmutation of one chemical element to another, and also differentiated and named alpha and beta radiation,[3] proving that the former was essentially helium ions. -
Neils Bohr
As a theory, it can be derived as a first-order approximation of the hydrogen atom using the broader and much more accurate quantum mechanics, and thus may be considered to be an obsolete scientific theory. -
Werner Heisenberg & Erwin Schrodinger
Edwin Schrodinger stated that rather than electrons being distributed within an electron.
