1. Launch: 11/5
 Grab your binder and immediately take a seat!
 Place homework (practice questions) on desk
1. Draw the correct Lewis structures for the following
atoms. Be sure to use the 3-steps!
i. HI
ii. PH3
iii. O2

2. Schedule
 We have an exam in 5 days!
 We don’t have time to waste!
 Follow our 7 class rules
 You may not use inappropriate language
 If you have a question, ask!

3. What are the two types of
covalent bonds?
Mr. Heffner
11/5/09

4. What are the two types of
covalent bonds?
 The two types of covalent bonds are…
1. Non-polar covalent bonds:
 Electrons are equally shared
H H
• •
Shared in the middle

5. What are polar bonds?
 The two types of covalent bonds are…
2. Polar covalent bonds:
 Electrons are unequally shared
• •
H Cl
• •
Closer to Cl, but still
shared!
• • • •

6. Why are electrons shared
unequally?
 Electrons are shared unequally because..
 of differences in electronegativity
 electronegativity = how strong (and greedy) atoms are

7. Why are electrons shared
unequally?
Non-polar Polar
covalent covalent Ionic
.5 1.7
Shared equally
Shared unequally
Ripped off
(transferred)

8. Why are electrons shared
unequally?
 There is a 3-step method for determining whether a
bond will be

9. Example #1
Is H – H a nonpolar covalent or polar covalent bond?
 Step 1: Find electronegativity
 H = 2.1
 H = 2.1

10. Example #1
Is H2 a nonpolar covalent or polar covalent bond?
 Step 2: Subtract electronegativities
 2.1 – 2.1 = 0

11. Example #1
Is H2 a nonpolar covalent or polar covalent bond?
 Step 3: check number line
 0 is less than .5
Non-polar Polar
Ionic
covalent covalent
.5 1.7

12. Example #2
Is HCl a nonpolar or polar covalent bond?
 Step 1: Find electronegativity
 H = 2.1
 Cl = 3.0

13. Example #2
Is HCl a nonpolar covalent or polar covalent bond?
 Step 2: Subtract electronegativities
 3.0 – 2.1 = .9

14. Example #2
Is HCl a nonpolar or polar covalent bond?
 Step 3: check the number line
 .9 is between .5 and 1.7
Non-polar Polar
covalent covalent Ionic
.5 1.7

15. Example #3
Is NaCl a nonpolar covalent, polar covalent bond, or ionic bond?
 Step 1: Find electronegativity
 Na = .9
 Cl = 3.0

16. Example #3
Is NaCl a nonpolar covalent, polar covalent bond, or ionic bond?
 Step 2: Subtract electronegativities
 3.0 – .9 = 2.1

17. Example #3
Is NaCl a nonpolar covalent, polar covalent bond, or ionic bond?
 Step 3: less than .5, between .5 and 1.7, or greater than
1.7?
 2.1 greater than 1.7

18. Exit Slip
1. In polar covalent bonds
a. electrons are equally shared due to similarities in the
number of valence electrons
b. electrons are unequally shared due to differences in
electronegativities
c. electrons are transferred from from one atom to the
other
d. atoms can have more than 8 valence electrons

19. Exit Slip
2. Non-polar covalent bonds form when electronegativity
differences
a. are less than .5
b. more than .5, but less than 1.7
c. more than 1.7
d. between .5 and 1.7

20. Exit Slip
3. The bond in HI is
a. non-polar covalent
b. ionic
c. metallic
d. polar covalent

21. Exit Slip
4. Which of the following is a polar covalent bond
a. H–H
b. H–P
c. H – Cl
d. H – Na

22. Exit Slip
5. Which of the following is a non-polar covalent
compound
a. NaCl
b. Fe3+
c. CH4
d. AlCl3

23. Homework
 Finish Lewis symbol and ions worksheet