Dalton & the Solid Ball Model
The second person to think about how atoms worked and the first person to actually propose an idea of what the atom looked like was John Dalton. Dalton was an Englishman who started teaching when he was in his early teenage years. A part time scientist, Dalton imagined the atom to be a solid ball that was too small to see. A small pile of any substance, like gold, meant that you had less atoms than a larger pile of the same substance. From his research in the years 1803-1807, Dalton proposed four laws that governed atomic theory:
1. Each element is made of tiny particles called atoms.
2. The atoms of a given element are identical; the atoms of different elements are different in some fundamental way or ways.
3. Chemical compounds are formed when atoms combine with each other. A given compound always has the same relative numbers and types of atoms.
4. Chemical reactions involve reorganization of the atoms-changes in the way they are bound together. The atoms themselves are not changed in a chemical reaction.