1. Aka Dot Diagrams Electron Dot Diagrams
Lewis Dot Structures
Aka Dot Diagrams
Electron Dot Diagrams

2. Valence electrons are the electrons on the outermost energy level.
6 valence electrons on this atom.
Review - Students know this already
Image from Wikipedia

3.      1s 2s 2p
Valence electrons
The final s and p valence electrons are especially important because they determine what kinds of reactions an atom will undergo.
Have a student read this out loud

4. Example: Tin, Sn: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p2
If you write the Shorthand Configuration for an element, the s and p electrons on the highest energy level are the valence electrons.
Example: Tin, Sn:
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p2
Have a student read this out loud. The arrow and boxes animate in on a mouse click.
valence electrons

5. Lewis Dot Structures show only the Valence electrons for an element.
A Dot Diagram consists of two parts:
the element symbol
dots that represent the S and P block electrons
Dots may only go on the sides of the element symbol Sn
Have a student read this out loud, Each bullet animates in on a mouse click.

6. Rules for Writing Lewis Dot Diagrams:
Only use s and p valence electrons
If there are d or f valence electrons in between the s and p sublevels, they are left out of the dot diagram.
Have a student read this out loud. The no symbol animates in on mouse click.
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p2

7. Rules for Writing Lewis Dot Diagrams:
You must put 1 electron dot on each side of the element symbol before you put 2 on one side (like Hund’s rule) El El
Have a student read this out loud. The element symbol comes in on mouse click and the dots and no sign come in automatically 1 second apart.
For example: Imaginary Elementium (El) has 3 valence electrons (5s2 and 5p1)

8. Sn Example: Tin, the last electrons are 5s2 4d10 5p2.
For the dot diagram, we will use only the valence electrons 5s2 and 5p2.
Therefore we will place 4 dots around the element symbol. Sn
Have a student read this out loud. The dots and squares com in on mouse clicks.
= places where electrons can go
Don’t draw it, just think it

9. A total of 7 electron dots.
Example: Bromine
Shorthand Configuration is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5.
Use only the 4s2 and the 4p5.
A total of 7 electron dots.
Have a student read this out loud. Dots come in automatically after 1 mouse click. Br

10. Practice problems Neon Sodium Aluminum
Give them some time to practice – maybe 3 minutes. Then show them the answers on the next slide

11. Ne Na Al Answers to Practice
No, it does not matter which side has no electron dots as long as there are the correct number of sides without dots.
Show them answers for a few seconds before showing them the assignment slide. Al

12. Assignment Complete the Dot Diagram Periodic Table Assignment.
Answer all questions.
Be sure to label your Dot Diagram Periodic Table when the instructions say to.
You will turn them in next week (Tuesday)