1. Molecules and Compounds
Valence Electrons, Octet Rule, and Lewis Dot Structures

2. ESSENTIAL QUESTION
Explain why the valence electrons are important when looking at the periodic table.

3. Atoms combine to make molecules
Most atoms are unstable unless combined with other atoms to make molecules and compounds!!
Molecules
Why combine?

4. Formed when atoms combine
Electrons in the outermost part of the electron cloud surrounding the nucleus.
The ones that do the bonding!!
Chemical Bond
Valence e-

5. There are many energy levels around the nucleus
Can hold up to 2 electrons
What element is this???
Energy Levels
First E.L.

6. Second E.L.
What element is this??
Third E.L.
Can hold up to 8e-
Can hold up to 8e-!

7. Atoms form bonds to complete their octet (8 e-) and become stable
Have 8 valence electrons!
Octet Rule
Chemically-stable atoms

8. Complete this chart:

9. Elements in each group have the same number of valence e- with the exception of the transition metals
Use P.T. to find Valence e-

11. Represent the valence e-
Represents nucleus and all e- except for valence e-
Each dot = 1 e-
Dot Diagrams
Element Symbol
Up to 8 dots

12. Examples: H C Cl Mg N Ar Al O

13. Reflection: How do we write Dot structures
Reflection: How do we write Dot structures? Why are valence e- important?