Atoms and isotopes

Democritus

Initial atomic theory • thought that an atom was something that can be broken in half till it can’t anymore

Aristotle

Thought everything was made of the 4 elements • atoms can be divided indefinitely

John dalton

Revised Democritus atomic theory • created the 5 postulates

1st postulate • John dalton

All matter is composed of atoms

2nd postulate • John Dalton

Atoms are the same size

3rd postulate • John Dalton

Atoms can’t be broken down further

4th postulate • John dalton

Atoms can combine into different ratios

5th postulate • John dalton

Atoms are combined, separated, and rearranged in chemical reactions

JJ Thomson

Came up with cathode ray experiment

Ernest Rutherford

Came up with gold foil experiment

Niels Bohr

came up with the planetary model, found that electrons were moving in orbits around the nucleus bc of pos charge

Erwin Schrödinger

Came up with the double slit experiment

James Chadwick

Came up with the polonium Geiger experiment

Werner Heisenberg

Came up with the clouds of probability model using Bohr and schrödingers work