Download KEY DEMOCRITUS • All matter is made of tiny particles • Solid

DEMOCRITUS


DALTON


THOMSON



KEY
All matter is made of tiny particles
Solid sphere model of atom
Atomic Theory
o All elements are made of atoms
o All atoms of an element are identical
o Atoms are not created or destroyed
Solid sphere model of atom
Discovered the electron
Cathode ray tube experiment
o Beam of electrons was…
o attracted to positive end of magnet
o repelled by negative end of magnet
Plum pudding model of atom
MILLIKAN


Discovered charge of the electron
Oil drop experiment
o Sprayed a fine mist of oil.
o Gave oil droplets a charge.
o Measured the rate that they fell through chamber.
RUTHERFORD



Discovered the nucleus
Concluded the atom is mostly empty space.
Gold foil experiment
o Expected particles to go through plum pudding.
o Most particles did!
o Instead, particles occasionally collided with nucleus & bounced back.
BOHR

Planetary model of atom
QUANTUM
MECHANICAL
MODEL


Electron cloud
Model of the atom that we use today