1. The History of the Atomic Theory

2. Democritus 300 BC Atom the indivisible; cannot be further broken down into smaller pieces". The atom as the smallest particle of matter.

3. Daltonc.1800 - Atoms are seen as solid, indestructible spheres (like billiard balls) - Explains how atoms combine to form molecules. - Confirms basic Laws of Chemistry: “Conservation of Mass and “Conservation of Mass and Definite Proportions”. Definite Proportions”.

4. JJ Thomson C. 1850 Chocolate chip cookie model :Chocolate chip cookie model : Atoms are solid spheres made-up of a solid positive mass (or core) with tiny negative particles embedded in the positive core. Atoms are solid spheres made-up of a solid positive mass (or core) with tiny negative particles embedded in the positive core.

5. Rutherford 1905 Famous Gold Leaf Experiment.Famous Gold Leaf Experiment. Proved the atom is mostly made of empty space.Proved the atom is mostly made of empty space. Proved that the nucleus is Proved that the nucleus is positive and the electrons are positive and the electrons are outside the nucleus. outside the nucleus.

6. Bohr 1920 Electrons in definite energy levels around the nucleus.Electrons in definite energy levels around the nucleus. Proved that electrons are placed in definite energy levels (called Orbitals) around the nucleus.Proved that electrons are placed in definite energy levels (called Orbitals) around the nucleus. Speaks of Neutrons in the nucleusSpeaks of Neutrons in the nucleus * 2, 8, 8, 2 *

8. Atomic Review Video Atomic Review Video Main Principles: - All matter is made up of tiny particles called atoms. - All matter is made up of tiny particles called atoms. -Atoms are made of even smaller particles: Protons (+), Electrons (-), and Neutrons (o)

9. -Atoms can be distinguished from each other by their number of protons, electrons and neutrons. Periodic Table of Elements

10. What the heck does it mean? Each element is broken down the same way.