-
400
democritus
major contribution proposed the at matter was formed of small pices that canot be broken down -
400
aristotle
Major contriution stared all substances ar made of 4 element 1 fire 2 water 3 air 4 earth -
jhon dalton
transformed democritus ideas on atoms into a modern atomic model -
J.J. Thompson
j.j. thompson discoverd electrons in a sires of experements -
robert millikan
major contubution determined the amout and charge of the electron -
Ernest rutherford
major contribution discoverd the radioictive -
nelis bohr
he dicoverd orbits -
sir james chadwick
he dicoverd neutrons
