1. Focus on the WHITE words
22.1 Notes Part A
Focus on the WHITE words

2. Objectives
Describe how the properties of compounds differ from those of their constituent atoms.
Explain what a chemical formula represents.
Discuss why chemical bonding occurs.

3. Atomic Structure Review
Atoms are made up of protons, neutrons, and electrons
Individually, atoms have the same number of p+ and e-

4. Atomic Structure Review
If an element has 8 protons, how many electrons does it have?
If an element has 53 electrons, how many protons does it have?
8 electrons
Element = Oxygen
53 electrons
Element = Iodine

5. Atomic Structure Review
The number of electrons in an atoms valence shell is NOT the total number of electrons in that atom (except for H and He)
Valence shell = outer electron shell

6. Lewis Dot Diagrams
Valence Electrons are represented as dots or Xs around the chemical symbol of an element
Traditionally written along the sides of an imaginary box
No more than 2 electrons on each side

7. Examples

8. Lewis Dot Diagrams Used to illustrate how electrons rearrange in bonds
Example:

9. In-Class Assignment/Homework
Lewis Dot Diagrams – Elements
Lewis Dot Diagrams – Compounds