Atomic Theory

Discovered the nucleus

• Democritus
• Robert Millikan
• James Chadwick
• Ernest Rutherford

Discovered the neutron

• Ernest Rutherford
• James Chadwick
• Joseph Thomson
• John Dalton

Idea was of an indivisible particle of matter he called "atomos"

• John Dalton
• Aristotle
• Democritus
• Plato

Discovered the electron using cathode ray tube

• Joseph Thomson
• John Dalton
• Ernest Rutherford
• Robert Millikan

Believed matter was continuous and discredited Democritus' theory

• Plato
• Galileo
• Aristotle
• Democritus

Atomic model was termed the "plum pudding model"

• Joseph Thomson
• Niels Bohr
• Ernest Rutherford

Discovered the proton in 1920

• James Chadwick
• Ernest Rutherford
• John Dalton
• Niels Bohr

His atomic model was depicted similar to a planetary/solar system

• Niels Bohr
• Joseph Thomson
• Ernest Rutherford

First measured the mass and charge of an electron

• Joseph Thomson
• Robert Millikan
• John Dalton
• Niels Bohr

His atomic model included a dense positive core in an atom, surrounded by negatively charged particles

• Joseph Thomson
• Niels Bohr
• Ernest Rutherford