1. Chemistry Lewis Structures
If H2O is the formula for water, what is the formula for ice? H2O cubed.

2. Valence Electrons Recall:
Valence Electrons are electrons located on the outer orbit
E.g.

3. Lewis Structures
When atoms form compounds, valence electrons are the ones that are involved in the bonding
Valence electrons are the electrons found in the outermost orbit (energy level)
Lewis structures show atoms depicting their valence electrons only – much easier then Bohr-Rutherford Diagrams

4. Rules
Symbol of the element is in the center and represents protons, neutrons and inner electrons (electrons not in outer orbit)
The symbol is assumed to have 4 sides, and the electrons in the outermost energy level are placed as dots on the four sides.
Dots are placed singly, and are then paired up in the order (N S E W).

5. How do we know the number of Valence Electrons an atom has?
Valence electrons are the electrons in the outer orbit surrounding an atom in a Bohr-Rutherford Diagram
What is the shortcut to finding the number of valence electrons?

6. Shortcut
Find the group number the element is in while skipping the transition metals
The group number = the number of valence electrons