Atomic structure

Atomic structure

1. Democritus-Greek philosopher

   • believed that all matter was composed of tiny particles: Atomos -Atoms- invisible,indestructible,indivisible
   • the idea was rejected by others-he could not answer how atoms were held together

2. Atonine Laveisier(1743-1794)

   • Law of Conservation of Matter
     • very accurately measured the mass of substances before and after a chemical reaction are found that they were the same
   • energy and matter is neither created nor destroyed

3. Joseph Louis Preust(1754-1826)

   • Law of Constant Composition
     • Given compound always contain the elements in the same proportion by Mass
     • water (H2O): 88.9% oxygen, 11.1% hydrogen

4. John Dalton(1766-1844)

   • All elements are composed of particles called atoms
   • atomos of the same elements are identical and different from atoms in other elements
   • atoms of different elements can combined to form compounds, any given compound has the same relative amount and types of atoms
   • chemical reactions occur when atoms are separated, joined, or rearranged, but the actual atoms do not change (created/destroyed)