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Period: to
Key discoveries in atomic structure
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John Dalton
-contribution to theory-atoms combine in whole # ratios & chemical reactions re-arrange atoms-law of multiple proportions, definite proportions, conservation of mass
-experiments-mixing gases and different absorption rates of water for different gases -
JJ Thompson
-contribution to atomic theory-all atoms have neg. charged particles with little mass and pos. charged particles with more mass
-experiments-cathode ray tube experiment measured angle of deflection and mass to charge ratio of particles -
Einstein
-contribution to atomic theory-light is made of particles called photons carrying a quantum of energy-for photoelectric effect to occur electrons must be with a photon of minimum energy and frequency
-experiments-photoelectrice effect-shine certain lights on different metals-if the right frequency then metals eject electrons -
Rutherford
-contribution to atomic theory-atoms mostly empty space with a dense, positively charged nucleus
-experiments-shot alpha particles at gold foil-most went right through but some were deflected-measured angle of deflection -
Bohr
-contributions to atomic theory-electrons in quantized energy orbitals at specific distances from the nucleus-can move up in energy level then move down and release energy
-experiments-light emission spectrum of hydrogen and Rutherford's gold foil experiment -
de Broglie
-contribution to atomic theory-electrons behave like waves in quantized energy levels specific distances from the nucleus-light wavelength equation
-experiments-fired electron beam at crystal and observed that electrons reflected like waves rather than particles -
Pauli
-contribution to atomic theory-Pauli exclusion principle-no 2 electrons can have same 4 quantum #'s-must have opposite spins if in the same orbital
-experiments-theory based on other experiments -
Schrodinger
-contribution to atomic theory-created equation that treats electrons as waves-showed probability of finding electrons in certain regions-orbitals
-experiment-theory based on de Broglie experiments