History of Chemistry

John Dalton’s Modern Atomic Theory

-Matter is made up of atoms
-Atoms are indivisible & indestructible
-atoms of an element type are identical
-atoms of different elements have different weights
-atoms remain unchanged

JJ Thomson Cathode-Ray Tube Experiment

determined charge-to-mass ratio of electron / discovery of electron

JJ Thomson’s Plum-Pudding Model

atom consists of positive and negative charges, electrons spread throughout structure

Robert Milikan and the Oil Drop Experiment

discovered electron charge

Ernest Rutherford & the Gold Foil Experiement

discovered nucleus