1. Bohr Models and Lewis Dot Structures

2. Atoms ** Basic unit of matter Consists of: Electrons, Protons, & Neutrons

3. +1 +2+3+/-4-3-2 0 -5 = element charges= Valence Electrons I II IIIIVVVIVII VIII

4. Element a pure chemical substance consisting of one type of atom Atomic Number= Number of Protons = Number of Electrons Symbol Name Mass Number = Number of Protons + Number of Neutrons

5. Bohr Models Proposed by Niels Bohr in 1915 Electrons orbit the nucleus in orbits that have a set size and energy. The energy of the orbit is related to its size. The lowest energy is found in the smallest orbit.

6. Energy Levels When two atoms approach each other, the nuclei do not touch Only Electrons are involved in Chemical Reactions Electrons feel each other first MOST IMPORTANT particle for bonding! WATCH THIS!

7. Bohr Models ** Show just electrons with energy levels 1 st level holds 2 2 nd holds 8 3 rd holds 18 but is stable at 8 4 th holds 32 but is stable at 8

8. Try Some Carbon – Number of p/n/e – Draw Bohr Model

9. Try Some Nitrogen –Number of p/n/e –Draw Bohr Model –Try some from Worksheet!!!!

10. Valence Electrons Electrons that are found on the outer most energy level. This determines the elements chemical properties

11. How to draw a Bohr Model?

12. Lewis Dot Structures Show only valence electrons Show only those electrons on outer energy level