ATOMIC THEORY

DEMOCRITUS

ATOMOS THEORY

• Everything is made of atoms
• Atoms are always in motion
• Theory was correct, but was thought to be incorrect

ARISTOTLE

EARTH/WIND/FIRE/WATER

• Theory was incorrect, but thought to be true
• Everything is made up of the four elements
• Influential

DALTON

BILLIARD BALL

• Atoms can be subdivided
• Atoms combine/seperate with atoms to make compounds in chemical reactions
• Agreed with Democritus's theory

JJ THOMSON

PLUM PUDDING

• Smaller parts make up an atom
• Plum pudding theory
• Electrons and protons

RUTHERFORD

POSITIVELY CHARGED NUCLEUS

• One proton in nucleus
• Electrons surround proton
• Gold foil experiment

MILLIKAN

MASS/CHARGE OF ATOM

• Oil drop experiment
• Electrons: negative charge
• Atoms have different charges

CHADWICK

PROTON NEUTRON

• Proton is inside
• Nucleus is inside
• Electrons are outside