1. Launch: 11/3
 Grab your binder and immediately take a seat!
1. Draw the correct Lewis symbols for the following atoms:
i. hydrogen
ii. neon
iii. nitrogen
iv. bromine
v. strontium

2. Schedule
 Monday (11/2): Covalent Bonds
 Tuesday (11/3): Covalent Bonds
 Wednesday (11/4): Covalent Bonds
 Thursday (11/5): Covalent Bonds
 Friday (11/6): Chemical Bonding Review
 Monday (11/9): Chemical Bonding Review
 Tuesday (11/10): Chemical Bonding Unit Exam!

3. Schedule
 We don’t have time to waste!
 Follow our 6 class rules
 If you have a question, ask!
 Ask your partner
 Ask me

4. What are Lewis
structures?
Mr. Heffner
11/3/09

5. Review: Octet Rule
 Octet Rule:
 all atoms want to have 8 valence electrons
• • • •
 like the noble gases
Ne F
• •
• •
• •
• • • • •
8= 7=

6. Review: Covalent Bonding
 To get 8, two nonmetals share electrons
• • • •
F F
• •
• •
•
• • • • •
7= 7=

7. Review: Covalent Bonding
 To get 8, two nonmetals share electrons
Covalent
• • • •
F F
Bond
• •
• •
• •
• • • •
8= 8=

8. What are Lewis structures?
 Lewis structures are…
 used to represent covalent bonds between atoms
• •
Ne
• •
Lewis Symbol
• • • •

9. What are Lewis structures?
 Lewis structures are…
 used to represent covalent bonds between atoms
• • • •
Covalent Bond
F- F
2 electrons = dash
• •
• •
Lewis
Structure
• • • •

10. What is a Lewis structure?
 There is a 3-step process for creating Lewis
structures:
1. Draw Lewis symbol for each atom and count dots
2. Arrange atoms so they all have a full octet
 If more than 2 atoms, place first atom in center
3. Count dots and convert shared pairs to bonds

11. Example
Draw the Lewis structure for Cl2
 Step 1: Draw Lewis symbol for each atom and count
• • • •
dots
Cl Cl
•
• •
• •
•
• • 14 dots • •

12. Example
Draw the Lewis structure for Cl2
 Step 2: Arrange atoms so they have a full octet
• • • •
Cl Cl
• •
• •
• •
• =• 8• •
8 =

13. Example
Draw the Lewis symbol for Cl2
 Step 3: Count dots and convert shared pairs to dashes
• • • •
Covalent Bond
Cl-Cl
2 electrons = dash
• •
• •
• •
• •
• • dots
14

14. Example
Draw the Lewis structure for NH3
 Step 1: Draw Lewis symbol for each atom and count
• •
dots
•
•
•
N HHH
•
•
• 8 dots

15. Example
Draw the Lewis structure for NH3
 Step 2: Arrange atoms so they have a full octet
 If more than two atoms, place first atom in center
• •
HN H
• •
H is an exception to
• • • •
H
the octet rule
2= 8=

16. Example
Draw the Lewis structure for NH3
 Step 2: Arrange atoms so they have a full octet
 If more than two atoms, place first atom in center
• •
H-N-H • •
• •
•
- •
H 8 dots

17. Example
Draw the Lewis structure for HCl

18. Whiteboards
 Work in pairs
 Trade-off marker every question
 You have 60 seconds to draw the answer
 Show all three steps!
 Lift board only when prompted

19. H2

20. Br2

21. SH2

22. CH4

23. Practice Questions
 Practice Questions worksheet

24. Exit Slip
1. In order to achieve a stable octet, two nonmetals
a. form ionic bonds by transferring electrons.
b. form ionic bonds by sharing electrons.
c. form covalent bonds by sharing electrons.
d. form metallic bonds by sharing electrons.

25. Exit Slip
2. See whiteboard.

26. Exit Slip
3. Which of the following correctly identifies the
Lewis structure for HF?

27. Exit Slip
4. Bubble in A
Then, draw the Lewis structure for HI

28. Exit Slip
5. Bubble in A
Then, draw the Lewis symbol for CBr4

29. Homework
 Finish Lewis symbol and ions worksheet