The Atom

The Atom

1. School Teacher John Dalton proposed atomic theory

   • Believed Atoms of a particular element are identical
     • Was Wrong about that
   • Said "Atoms cannot be subdivided"
     • Found later that they can be subdivided
   • Explained the "law of definite composition"
     • ex. the fact that the mass ratio of two elements in a compound is constant
   • Correct about "All Matter is composed of Atoms" and "Atoms of different elements are different in size and shape"

2. Law of multiple proportions

   • ex. lead forms two oxides of different formulas

3. Particles pass from Cathode to Anode

4. Contains small, densely packed, positive region in the middle

   • Revealed through some atoms bouncing back off of foil
   • Rutherford discovered this
     • Conducted this experiment