Atomic Theory – People & Contributions

Greek philosopher – first description of an “atom”

English chemist/physicist – Dalton’s Atomic Theory

Swedish physicist – Rydberg formula which predicts wavelengths of light emitted from e- changing energy levels in an H atom

English physicist- discovered the electron and the charge/mass ratio of the electron – plum pudding model of the atom

German physicist – originator of Quantum Theory, Planck’s constant – all energy is emitted/absorbed in discrete packets called quanta

German physicist – wave-particle duality of light – photons, explanation of photoelectric effect

American physicist – Oil-Drop experiment determined the charge on an electron

New Zealand/English physicist – gold foil experiment – discovered that the mass and positive charge of an atom is in the nucleus

Danish physicist – Bohr model of the atom – e- in orbits at certain energy levels

English physicist – linked atomic number to a real physical quantity

French physicist – wave-particle duality for all matter

Austrian physicist – Pauli Exclusion Principle – electrons occupying the same orbital must have opposite spins

German Physicist – Hund’s Rule – electrons are placed in separate orbitals of the same energy before a second is placed in any

Austrian physicist – wave equation which describes changes in the quantum state of a physical system over time

German physicist – Heisenberg Uncertainty Principle – key development of quantum theory, you cannot know precisely where a particle is and where it is going

English physicist – discovered the neutron