1. J OHN D ALTON ' S ATOMIC THEORY

2. J OHN D ALTON English, 1766-1844 Chemist, meteorologist and physicist Careful study of Red – green color blindness Atomic theory, gas law, atomic weight

3. D ALTON ’ S T HEORY All matter is composed of indivisible particles called atoms.

4. Atoms are indivisible and indestructible.

5. Atoms of the same element are identical to one another in mass and other properties.

6. Atoms combine in simple whole number ratios to form compounds.

7. Atoms of an element are not changed into atoms of a different element by chemical reactions.

8. Dalton was even the first to make an attempt at creating a table of atomic weights

9. D ALTON ’ S FORMULAS Chemical reactions involve the rearrangement of atoms.

10. S HORTCOMINGS OF D ALTON ’ S ATOMIC MODEL the discovery of nuclear fission and fusion Isotopes Atoms are not empty, there are empty spaces in atoms.

11. W HY DID PEOPLE BELIEVE D ALTON ? He had EVIDENCE! Dalton found that compounds always contained the same mass ratio of one element to another This is now known as the “Law of Definite Proportions” Elements could combine in different ratios, but when they did, they would make different compounds. This is now known as the “Law of Multiple Proportions”

12. T HANK YOU FOR YOUR ATTENTION