-
Democritus brought the theory that matter is made of atoms separated by empty space where atoms move through. -
John Dalton proposed that all matter was composed of atoms and that all atoms of an element were identical and atoms of other elements varied in mass and size. -
Discovered that when the elements were arranged based on the atomic weight it resulted in a table with a recurring pattern. The periodic table -
Goldstein discovered the proton -
J.J Thomson discovered the electron and proposed the atom as a sphere of positive matter with electrons in positions based on electrostatic forces. -
Discovered that energy was always emitted in tiny packets called a quantum of energy. He started a new field called quantum mechanics. -
He determined the electric charge of a single electron. -
Ernest rutherford postulated the nuclear structure of the atom. -
Bohr suggested that electrons move around the nucleus in a fixed orbit and if electrons change orbit it results in radiation. -
Erwin Schrödinger proposed the quantum mechanical model of the atom which treats electrons as matter waves. -
Discovered the uncertainty principle, which means that an electron's position and momentum can not both be known at the same time. -
James Chadwick is responsible for discovering the neutron.