1. Bohr Diagrams

2. Bohr Diagrams Picture representation of an atom.
Gives info about the nucleus, electrons, and energy levels.

3. Steps to drawing a Bohr Diagram:
1. Write symbol, # of protons and # of neutrons.
# of protons
Symbol
27-13 = # of
neutrons

4. Steps to drawing a Bohr Diagram:
2. Add # of circles around this for # of energy levels needed (same as period #).
Elements in the 1st period have one energy level.
Elements in the 2nd period have two energy levels, and so on.

5. Steps to drawing a Bohr Diagram:
3. Add electrons to each orbital.
Atomic # = # of protons = # of electrons
Electrons are filled in as follows:
1st = 2 e-
2nd = 8 e-
3rd = 18 e-

6. Example: Aluminum

7. Example:

8. Example:

9. Electron Dot Diagrams

10. Electron Dot Diagrams
Element's symbol surrounded by dots that represent the valence electrons. 
An element will never have more than eight valence electrons.

11. Valence Electrons: The # of electrons in the outermost energy level.
# of valence electrons stays the same up/down a group, but increase across the periodic table.
They get most involved in chemical reactions.

12. How to determine the # of valence electrons?

13. Example: Silicon

14. Steps to drawing an Electron Dot Diagram:
1. Draw the symbol 2. Add dots around the symbol to represent the # of valence electrons. **These do not apply to transition metals.**

15. Example:

16. Example: