1. Thanks to Mrs. LaRosa www.middleschoolscience.com 2008
Drawing Atoms
How to Draw Bohr Diagrams
Thanks to Mrs. LaRosa
2008

2. Bohr Diagrams Determine the number of protons:
# protons = atomic number
This is how many protons will go in the nucleus.

3. Bohr Diagrams Now figure out how many neutrons.
Neutrons = Atomic Mass (round off)-# protons.
This is how many neutrons will go in the nucleus.

4. Bohr Diagrams Determine the number of electrons
# electrons = # protons
This is how many electrons you will draw in the energy levels or energy clouds.

5. Bohr Diagrams Find out which period (row) your element is in.
Elements in the 1st period have one energy level.
Elements in the 2nd period have two energy levels, and so on.

6. Where do the electrons go?
Putting electrons into an atom is like filling seats at a concert:
First row fills up first, then second row, then third row.
Each energy level has a limited number of spots (like seats in a concert)
First energy level: 2 electrons
Second energy level: 8 electrons
Third energy level: 8 electrons

7. Bohr Diagrams
Carbon
Draw a nucleus with the correct number of protons and neutrons inside.
Carbon is in the 2nd period, so it has two energy levels or clouds.
Draw the energy levels around the nucleus.
p+=6
n=6

8. Bohr Diagrams Add the electrons. Carbon has 6 electrons.
The first level can only hold 2 electrons.
p+=6
n=6

9. Bohr Diagrams
Since you have 2 electrons already drawn, you need to add 4 more.
These go in the 2nd energy level.
Add one at a time -starting on the right side and going counter clock-wise.
p+=6
n=6

10. Bohr Diagrams Check your work.
You should have 6 total electrons for Carbon.
Only two electrons can fit in the 1st level.
The 2nd level can hold up to 8 electrons.
The 3rd level can hold 8, but Carbon doesn’t use that level.
p+=6
n=6

11. O Bohr Diagrams Try the following elements on your own: 8 protons
8 neutrons
2 energy levels
8 electrons
p+=8
n=8

12. Al Bohr Diagrams Try the following elements on your own: 13 protons
14 neutrons
3 energy level
13 electron
p+=13
n=14

13. Ar Bohr Diagrams Try the following elements on your own: 18 protons
22 neutrons
3 energy levels
18 electrons
p+=18
n=22

14. H Bohr Diagrams Try the following element on your own: 1 proton
0 neutrons
1 energy level
1 electron
p+=1
n=0

15. Bohr Diagrams Try the following elements on your own: H
He - 2 electrons O Al Ne Ar
p+=2
n=2

16. Bohr Diagrams Try the following elements on your own: H He O Al
Ne - 10 electrons Ar
p+=10
n=10

17. Bohr Diagrams
End of Study Guide. You should know how to draw a Bohr Diagram for the first 18 elements.