Development of Atomic Theory first half

Democritus

first atomic theory - no experimentation

Lavoisier

Law of Conservation of Mass

Proust

Law of Definite Composition

Dalton

billiard ball model

Crookes

discovers cathode rays

Thomson

measured charge-to-mass ratio of the electron

electrons are part of all matter

Millikan

"oil drop" experiment electrons have a specific charge

Rutherford

"gold foil" experiment (3 observations and 2 conclusions)

Bohr

hydrogen line spectra

Chadwick

discovered the neutron

Dalton

first modern atomic theory (5 statements)

Thomson

"discoverer of the electron"

Thomson

"Plum pudding" model of the atom

Millikan

measured the charge of the electron

Bohr

"solar system" atom

energy levels

Arrhenius

atoms form ions

Faraday

atoms lose or gain specific numbers of electrons, electricity is the glue that holds chemicals together

Thomson and associates

proton

Francis Aston

mass spectrometer

Soddy

Isotopes of an element - same proton, different neutron

Brookes

Elements turn into other elements when emitting radiation