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John Dalton
Dalton's atomic theory proposed that all matter was composed of atoms, indivisible and indestructible building blocks. -
J.J Thompson
J.J. Thomson's experiments with cathode-ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons. Thomson's plum pudding model of the atom had negatively-charged electrons embedded within a positively-charged "soup." -
Ernest Rutherford
he postulated the nuclear structure of the atom: experiments done in Rutherford's laboratory showed that when alpha particles are fired into gas atoms, a few are violently deflected, which implies a dense, positively charged central region containing most of the atomic mass. Rutherford's gold foil experiment showed that the atom is mostly empty space with a tiny, dense, positively charged nucleus. -
Neils Bohr
a physicist who made foundational contributions to understanding atomic structure and quantum theory. He came to the conclusion that electrons orbit in shells around the nucleus of an atom