Atomic theory QUIZ

Democritus

(atomist) Greek philosopher that said all matter is made of tiny particles called atoms. They exist! Said they were indivisible. problem included no protons neutrons or electrons/ no isotope data

Aristotle

Another greek philosopher. He said they all thing were made up of fire air earth and water.

What is the understanding now?

Atoms ARE divisible spheres. They are made up of protons(p+), neutrons(n°), and electrons(e-). They have a small dense nucleus. They are mostly empty space. They make up everything. Atoms of different elements will behave differently. You can have an atoms of an element change to another element (radioactive)

Main discovery of Milikan

Charge and mass of an electron

Earnest Rutherford

Gold foil experiment. Said the atom is mostly empty space. Discovered the nucleus. Used uniform line of radioactive alpha particle traveling through gold foil to see that some particle got rejected and hit the luminescent screen other places. Must be a small dense and positive nucleuse

Main discovery of Rutherford

Nucleus, must be small and dense, atom mostly empty space

Robert Millikan

Oil drop experiment. Used to determine the mass and charge of an electron. Oil misted into water and oil floated down onto electric plated through a magnetic field that determined the charge and mass

Main discovery of Thomson

Protons (and a little about electrons)

John Dalton

atomic theory. Came up with 5 laws (indivisible, same element behave the same, different behave different, law of definite proportions, atoms are broken formed and rearranged but never converted into new element) Only 3+4 are true

JJ Thomson

discovered the electron. Used cathode ray tube (crooks tube). Used tube to conduct a beam of some sort of energy that was negative because it bent away from the (-) side of a magnet. Invented plum pudding with negatives throughout, but later added the protons randomly throughout because there were other particles traveling off the cathode ray tube opposite direction.