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john dalton
everything can be separated into proportional elements. Atoms cannot be created or destroyed. his model of atoms was a solid ball. -
JJ Thomson
all atoms contain tiny negatively charged subatomic particles or electrons. His model was the plum pudding model. -
Ernest Rutherford
He shot alpha particles at gold foil and proved that atoms are mostly empty space with a nucleus. the atom had a central positive nucleus. The negatively charged electrons were in orbit around the nucleus of the atom. The atom as whole was neutral. The atom was mainly space. his model was protons in the middle with a nucleus and electrons flying around. -
Niels Bohr
Bohr was the first to discover that electrons travel in separate orbits around the nucleus and that the number of electrons in the outer orbit determines the properties of an element. -
James Chadwick
conducted an experiment in which he bombarded Beryllium with alpha particles from the natural radioactive decay of Polonium. His model was the quantum mechanical model.