1. Bohr Model Lewis Structure

2. Bohr Model Introduced in 1913 by Niels Bohr
Depicts the atom as a small, positively charged nucleus surrounded by electrons.
Why do we use the Bohr model?
Simple and easy to understand
Representation of subatomic particles
Valence Electrons

3. How to Draw Bohr Diagrams

4. Bohr Diagrams Find your element on the periodic table.
Determine the number of electrons – it is the same as the atomic number.
This is how many electrons you will draw.

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. Bohr Diagram Energy Level Electron Capacity 2 1 8 2 18 3 32 4 50 5 716 2 8 18 32 50 71

7. Bohr Diagrams Draw a nucleus with the p and n in the nucleus.
Carbon is in the 2nd period, so it has two energy levels, or shells.
Draw the shells around the nucleus.
Put how many protons
and neutrons in the center
P - 6
N- 6

8. Bohr Diagrams Add the electrons. Carbon has 6 electrons.
The first shell 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 shell.
Add one at a time -starting on the right side and going counter clock-wise. P N

10. Bohr Diagrams Check your work.
You should have 6 total electrons for Carbon.
Only two electrons can fit in the 1st shell.
The 2nd shell can hold up to 8 electrons.
The 3rd shell can hold 18, but the elements in the first few periods only use 8 electrons. P N

11. Bohr Diagrams Try the following elements on your own: H He O Al Ne K P

12. H Bohr Diagrams Try the following elements on your own: H – 1 electronAl Ne K H

13. Bohr Diagrams He Try the following elements on your own: H
He - 2 electrons O Al Ne K He

14. Bohr Diagrams O Try the following elements on your own: H He
O - 8 electrons Al Ne K O

15. Bohr Diagrams Al Try the following elements on your own: H He O
Al - 13 electrons Ne K Al

16. Bohr Diagrams Ne Try the following elements on your own: H He O Al
Ne - 10 electrons K Ne

17. Bohr Diagrams K Try the following elements on your own: H He O Al Ne
K - 19 electrons K

18. Lewis Structure Electron-dot diagrams
Represents paired and unpaired valence electrons in an atom
Covalent Bond- sharing electrons
Valence Electron- electrons in the outer most shell; electrons that are transferred or shared when atoms bond together

19. How to Draw Lewis Structures

20. Lewis Structures Find your element on the periodic table.
Determine the number of valence electrons.
This is how many electrons you will draw.

21. Lewis Structures Find out which group (column) your element is in.
This will tell you the number of valence electrons your element has.
You will only draw the valence electrons.

22. Groups - Review Group 8 = 8 electrons Group 1 = 1 electron
Except for He, it has 2 electrons
Group 2 = 2 electrons
Each column is called a “group”
3, 4, 5, 6, 7
Each element in a group has the same number of electrons in their outer orbital, also known as “shells”.
The electrons in the outer shell are called “valence electrons”

23. C Lewis Structures Write the element symbol.
Carbon is in the 4th group, so it has 4 valence electrons.
Starting at the right, draw 4 electrons, or dots, counter-clockwise around the element symbol. C

24. C Lewis Structures Check your work.
Using your periodic table, check that Carbon is in the 4th group.
You should have 4 total electrons, or dots, drawn in for Carbon. C

25. C Lewis Structures On your worksheet, try these elements on your own:P Ca Ar Cl Al C

26. H Lewis Structures On your worksheet, try these elements on your own:P Ca Ar Cl Al H

27. P Lewis Structures On your worksheet, try these elements on your own:Ca Ar Cl Al P

28. Ca Lewis Structures On your worksheet, try these elements on your own:P Ca Ar Cl Al Ca

29. Ar Lewis Structures On your worksheet, try these elements on your own:P Ca Ar Cl Al Ar

30. Cl Lewis Structures On your worksheet, try these elements on your own:P Ca Ar Cl Al Cl

31. Al Lewis Structures On your worksheet, try these elements on your own:P Ca Ar Cl Al Al

32. Complete the Lewis Structure Worksheet You should know how to draw Lewis Structures for the first 20 elements.

34. 1. The Bohr Model was introduced by which of the following scientists
Albert Einstein
Neils Bohr
Charles Darwin
Gregor Mendel
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35. 2. The Bohr model depicts
The atom as a small positively charged nucleus surrounded by electrons.
Paired and unpaired valence electrons in an atom.
Covalent bonds
Valence Electrons
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36. 3. In the periodic table, the rows represent
Groups
Covalent Bonds
Ionic Bonds
Periods
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37. 4. In the periodic table, the columns represent
Periods
Covalent Bonds
Groups
Ionic Bonds
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38. 5. The Lewis Structure represents
Paired and unpaired valence electrons in an atom.
The atom as a small positively charged nucleus surrounded by electrons.
Valence Electrons
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39. 6. When drawing a Bohr model, how do you determine the number of electrons?
Valence Electrons
Mass Number
Atomic Number
Atomic Mass Unit
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40. 7. When drawing a Lewis Structure, how do you determine the number of valence electrons?
Atomic Number
Mass Number
Atomic Mass Unit
By looking at the column the element is found in
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41. 8. The Lewis Structure is also known as
Bohr Model
The electron dot diagram
Valence Electrons
The planetary model
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42. 9. When drawing a Lewis Structure, in which direction do you move when drawing the dots?
Counter-clockwise around the element
Clockwise around the element
North
Southwest
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43. 10. When drawing a Bohr model, how do you determine the number of energy levels to use?
Groups
Columns
Periods
Atomic Number
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