Notes

- Democritus was an ancient Greek philosopher who lived from 460 BC to 370 BC. He was an influential philosopher who taught many things that were influential to people today. Democritus claimed that everything is made up of atoms. These atoms are physically, but not geometrically, indivisible. He believed that in between atoms is empty space. Atoms, he philosophized, are indestructible when in motion.

- John Dalton provided several ideas based on his atomic theory. He stated,
1. Matter is made up of extremely small particles called atoms which retain their individuality in all chemical transformations.
2. Atoms of the same element resemble one another in all respects and have different weights.
3. Atoms of different elements have different weights and posses different properties.
4. Atoms of different elements combine in simple but fixed ratio to form compound atoms.
5. Atoms are indestructible.
Dalton's Atomic Theory:
1 oxygen atom at 16 mass units each (16 mass units) + 2 hydrogen atoms at 1 mass units each (2 mass units) = 1 water molecule at 18 mass units each (18 mass units)
* All elements are composed of atoms (indivisible particles)
* All atoms of the same element are identical - in particular, they have the same mass.
* The atoms of one kind elements are different from the atoms of all other elements- in particular the atoms of one element have a different mass than those of other elements.
* Atoms are indestructible and retain their identity in chemical reactions.
*Compounds are formed by joining atoms in specific whole number ratios.