-
440 BCE
Democritus
-Atoms are "uncuttable"-
atoms are small, hard, particles
-atoms constantly move- -
440 BCE
Democritus
atomic model -
John Dalton
atomic model -
John Dalton
-all substances are made of atoms- atoms of different elements are different- atoms of the same element are exactly alike- elements combine in specific proportions- he conducted experiments in combining elements- -
J.J. Thomson
-He conducted the cathode-ray tube experiment- his theory of the atomic structure lead to the "plum-pudding" model- there are small, negatively charged particles inside an atom- -
J.J. Thomson
Atomic Model -
Ernest Rutherford
-Atoms contain mostly empty space- he conducted the gold foil experiment-most of an atom's mass is in the nucleus- there is a small, dense, positively charged nucleus- -
Ernest Rutherford
atomic model -
Niels Bohr
atomic model -
Niels Bohr
-electrons jump between levels from path to path- electrons move in empty space in the atom- electrons travel in definite paths- -
Erwin Schrodinger & Werner Heisenberg
-electron paths cannot be predicted- electrons are found in electron clouds, not paths- -
Erwin Schrodinger & Werner Heisenberg
Atomic Model
