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john dalton
discovered that oxygen combined with either one or two volumes of nitric oxide in closed vessels over water
He developed methods to calculate atomic weights and structures and formulated the law of partial pressures. Proposed that all matter was composed of atoms, indivisible and indestructible building blocks. While all atoms of an element were identical, different elements had atoms of differing size and mass -
jj thomson
discovered the electron and then went on to propose a model for the structure of the atom.
the electron and then went on to propose a model for the structure of the atom. His work also led to the invention of the mass spectrograph. cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons. Thomson proposed the plum pudding model of the atom, which had negatively-charged electrons embedded within a positively-charged "soup." -
ernest rutherford
discovered the nucleus of the atom established the nuclear theory of the atom with his gold-foil experiment. When he shot a beam of alpha particles at a sheet of gold foil, a few of the particles were deflected. He concluded that a tiny, dense nucleus was causing the deflections.. -
neils bohr
proposed a theory for the hydrogen atom, based on quantum theory that some physical quantities only take discrete values
based on quantum theory that some physical quantities only take discrete values. Electrons move around a nucleus, but only in prescribed orbits, and If electrons jump to a lower-energy orbit, the difference is sent out as radiation.