CHM 2046C Module-4iii Homework Packet Name: ____________________

Please complete the following homework sections before you attempt the exam. This is homework. You grade it. This completed packet is due the day of the exam. No credit for a section if the sample problem is shown and you leave any additional problems which do not show the answer blank.)

Module Four Part III: Chemical Bonding & Molecular Structure (Chapters 8-9)

B1 _____(07) Lewis Dot/Stick Structures via Formal Charge Steric #2-#6 Section 8.7 Answers

L1. ____ (01) Bond Angles/Bond Lengths Steric #5&6-Section 9.2 Answers

M._____ (00) Molecular Orbitals Section 9.7-9.8

N1. ____ (01) Geometry of Molecules-Steric #5&6 Section 9.1-9.2 Answers

O1. ____ (01) Polarity of Molecules- Steric #5&6 Section 8.6, 9.3 Answers

P1. ____ (01) Hybrid Orbital Recognition Steric #5&6-Sect 9.5-6 Answers

P2._____(00) Valence Bond Theory Section 9.4

Q. _____ (01) Formal Charge-Section 8.7 page 377-384 Answers

R. _____ (01) Resonance Structures Section 8.8 Answers

S. _____ (01) Sigma/Pi Bonding Section 9.6 Answers

______(14) Total

Module Four III: Part B1 Dot Structures of Molecules Review 7 points

Using a periodic chart draw the electron dot/stick structures of the following molecules. Use the method of formal charges to show the best structure: (Steric Numbers 2-6)

H₂SO₄ Also look at: H₂SO₃

Formal Charge

=

Valence Electrons

-

Nonbonding Val Electrons

-

Bonding e^1- 2

=

Total

H₃PO₄ Also look at: H₃PO₃

Formal Charge

=

Valence Electrons

-

Nonbonding Val Electrons

-

Bonding e^1- 2

=

Total

HClO₄ Also Look at: HClO₃ HClO₂ HClO

Formal Charge

=

Valence Electrons

-

Nonbonding Val Electrons

-

Bonding e^1- 2

=

Total

SO₂

Formal Charge

=

Valence Electrons

-

Nonbonding Val Electrons

-

Bonding e^1- 2

=

Total

SO₃

Formal Charge

=

Valence Electrons

-

Nonbonding Val Electrons

-

Bonding e^1- 2

=

Total

SF₆

Formal Charge

=

Valence Electrons

-

Nonbonding Val Electrons

-

Bonding e^1- 2

=

Total

SF₄

Formal Charge

=

Valence Electrons

-

Nonbonding Val Electrons

-

Bonding e^1- 2

=

Total

SbCl₅

Formal Charge

=

Valence Electrons

-

Nonbonding Val Electrons

-

Bonding e^1- 2

=

Total

PCl₅ Also look at PCl₃

Formal Charge

=

Valence Electrons

-

Nonbonding Val Electrons

-

Bonding e^1- 2

=

Total

AsF₅

Formal Charge

=

Valence Electrons

-

Nonbonding Val Electrons

-

Bonding e^1- 2

=

Total

SeF₆

Formal Charge

=

Valence Electrons

-

Nonbonding Val Electrons

-

Bonding e^1- 2

=

Total

HArF (first Nobel Gas Molecule)

Formal Charge

=

Valence Electrons

-

Nonbonding Val Electrons

-

Bonding e^1- 2

=

Total

Br₂^1-

Formal Charge

=

Valence Electrons

-

Nonbonding Val Electrons

-

Bonding e^1- 2

=

Total

XeF₄

Formal Charge

=

Valence Electrons

-

Nonbonding Val Electrons

-

Bonding e^1- 2

=

Total

XeO₄

Formal Charge

=

Valence Electrons

-

Nonbonding Val Electrons

-

Bonding e^1- 2

=

Total

BrCl₃

Formal Charge

=

Valence Electrons

-

Nonbonding Val Electrons

-

Bonding e^1- 2

=

Total

PCl₆^1-

Formal Charge

=

Valence Electrons

-

Nonbonding Val Electrons

-

Bonding e^1- 2

=

Total

BrF₄¹⁺

Formal Charge

=

Valence Electrons

-

Nonbonding Val Electrons

-

Bonding e^1- 2

=

Total

SO₂Cl₂

Formal Charge

=

Valence Electrons

-

Nonbonding Val Electrons

-

Bonding e^1- 2

=

Total

KrF₂

Formal Charge

=

Valence Electrons

-

Nonbonding Val Electrons

-

Bonding e^1- 2

=

Total

Other Ions/Compounds to consider which may be the exam question:

ClF₅ AsF₆^1- SeF₄ PF₃Cl₂ I₃^1- BrF₅

Reading Reference: Sections 8.5 Octet Rule and 8.7 Formal Charge (page 374)

Reference Octet Rule: B. Dot Structures of Covalent Compounds Section 2.10, 6.6, 7.1, 7.5, 7.6

Octet Rule Answers: http://www.fccj.us/chm2045/SampleTest/45M4bAnswers.htm

Module Four: Part L1 Bond Angles 1 point

Steric Numbers #2--#6. What is the bond Angle in the following structures:

______1. Bond Angle between O=S=O in Sulfur dioxide

______2. Bond Angle between any O = S = O in Sulfur trioxide

______3. Bond Angle between any F – Br – F in Bromine Trifluoride

______4. Bond Angle between any O = Xe = O in Xexon Tetroxide

_____5. Bond Angle between either O = S – O in Sulfuric Acid

_____6. Bond Angle Between either O = P – O in Phosphoric Acid

_____7. Bond Angle Between either O = Cl = O in Perchloric Acid

_____8. Bond Angle between any F – Xe – F in Xexon Tetrafluoride

____10. Bond Angle between any equatorial F – Br – F in Bromine Pentafluoride

____11. Bond Angle between axial F – Br and any equatorial F-B in Bromine Pentafluoride

____12. Bond Angle between any equatorial F – As – F in Arsenic Pentafluoride

____13. Bond Angle between either axial F – As and any equatorial F- As in Arsenic Pentafluoride

____14. Bond angle between axial F – As and the other axial F – As in Arsenic pentafluoride

Reading Reference: Jespersen 7^th Section 9.2; Note Figurer 9.4 page 408

Review Example 9.1 page 409

Try Practice Exercises 9.2/9.3 page 408

Study and Answer Review Questions #9.3-#9.7 page 458

Work End of Chapter Problems #9.73 -#9.90 pages 460-461 especially #9.81-9.82 and #9.83-9.84 page 461

Module 4iii Part N: Geometry of Molecules 1 point

Use the dot/stick structures on the Part L1 page to state the geometry of the molecules:

Steric Numbers 2, 3, or 4:

Trigonal Bent Linear Trigonal Planer Planer Trigonal Pyramidal Tetrahedral

Steric Numbers 5 or 6:

Trigonal-bipyramidal Square Planer Seesaw T-shaped Octahedral Other

_______________1. BrF3 _______________2. XeO4 _______________3. SO2 _______________4. SO3 _______________5. XeF4 _______________6. BrF5 _______________7. AsF5 _______________8. SeF6 _______________9. SeF4 _______________10. KrF2 _______________11. BrF3 _____________ Bonus C6H6

Benzene C6H6

Reading Reference: Jespersen 7^th Section 9.1/9.2 See Example 9.1 Page 409 See Steps page 413; See Example 9.4 Page415
Practice Exercise 9.1 page 406; Practice Exercises 9.2/9.3 Page 409; Practice Exercises9.4-9.6 Page 415

Look at End of Chapter Exercises #9,1-#9,7 page 458; Wrk Review Problems #9.73-#9.82 page 460-1

Module 4iii Part O: Polarity of Molecules 1 point

Sketch the 3D model of the molecule, show all dipoles; then decide if the molecule has a net dipole moment or not. Write Polar or Nonpolar in each blank.

_______________1. BrF3 _______________2. XeO4 _______________3. SO2 _______________4. SO3 _______________5. XeF4 _______________6. BrF5 _______________7. AsF5 _______________8. SeF6 _______________9. SeF4 _______________10. KrF2 _______________11. BrF3 _____________ Bonus C6H6

Benzene C6H6

Reading Reference: Section 8.6; Section 9.3

See Example 9.5 page 419 Work Practice Exercises 9.7/9.8 Page 420

Review Questions 9.8-9.15 pages 460-461

Try Problems 9.85-9.90 especially 9.89 and 9.90

Module 4iii - Part P1: Hybrid Orbitals of Molecules 1 point

Use the dot/stick structures in the table to predict the hybrid orbitals that overlap to form the covalent bond:

_____________1. BrF3 the sigma bond between either Br-F _____________2. XeO4 the sigma bond between either Xe=O _____________2a. XeO4 the pi bond between either Xe=O _____________3. SO2 the sigma bond between either S=O _____________3a. SO2 the pi bond between either S=O _____________4. SO3 the sigma bond between S=O _____________4a. SO2 the pi bond between S=O ____________ 5. XeF4 either sigma bond between any Xe-F ____________6. BrF5 either single (sigma) bond between Br-F ____________7. AsF5 the sigma bond between any of the As-F ____________8. SeF6 the sigma bond between any of the SeF6 ___________ 9. SeF4 either sigma bond between the As-F ___________ __10. KrF2 the sigma bond between either F-F _________ ____11. BrF3 either single (sigma) bond between Br-F _____________ 12. ClF5 either sigma bond between any Cl-F

What is difference between a Sigma (σ) and a pi (π) bond? What is a delta(Δ) Bond

Reading Reference Jespersen 7^th : Section 9.5 and 9.6
Try Practice Exercise 9.11 and 9.12 page 427; Look at Example 9.6 page 428 and 9.7 page 430-431

Try Practice Exercise 9.14 and 9.15 Page 431 Study Example 9.8Page 432 Do Practice Exercises 9.16 and 9.17 page 433, the 9.20 and 9.21 page 440

Module 4iii - Part Q: Formal Charge 1 point

1. Using the method of the octet rule, the following structure was drawn:

Assign the formal charge to each atom in the Lewis Structure by completing the table below: Show the nonzero formal charges on the Lewis structure by Placing them in circles alongside the atoms

Formal Charge	=	Valence Electrons	-	Nonbonding Val Electrons	-	Bonding e^1- 2	=	Total
S
O-
O=
O-

Sum of the formal charges in the molecule = ______

2. Using the method of the formal charge, the following structure was drawn:

Assign the formal charge to each atom in the Lewis Structure by completing the table below: Show the nonzero formal charges on the Lewis structure by Placing them in circles alongside the atoms

Formal Charge	=	Valence Electrons	-	Nonbonding Val Electrons	-	Bonding e^1- 2	=	Total
S
O=
O=
O=

Sum of the formal charges in the molecule = ______

Explain why the structure in #2 is more preferred than #1!

3.Using the method of the octet rule, the following structure was drawn:

Assign the formal charge to each atom in the Lewis Structure by completing the table below: Show the nonzero formal charges on the Lewis structure by Placing them in circles alongside the atoms

Formal Charge	=	Valence Electrons	-	Nonbonding Val Electrons	-	Bonding e^1- 2	=	Total
S
O=
O=
-O-
H-
-O-
H-

Sum of the formal charges in the molecule = ______

4. Using the method of the octet rule, the following structure was drawn:

Assign the formal charge to each atom in the Lewis Structure by completing the table below: Show the nonzero formal charges on the Lewis structure by Placing them in circles alongside the atoms

Formal Charge	=	Valence Electrons	-	Nonbonding Val Electrons	-	Bonding e^1- 2	=	Total
S
-O-
H-
-O
-O-
H-
-O

Sum of the formal charges in the molecule = ______

Explain why the structure in #4 is more preferred than #3!

Module 4iii - Part R: Resonance 1 point

1. Draw the Resonance Structures for Perchlorate Ion ClO₄^1-

2. Draw the Resonance Structures for Phosphate Ion PO₄^3-

3. Draw the Resonance Structures for Nitrite Ion NO₂^1-

4. Draw the Resonance Structures for Benzene C₆H₆ ; show resonance hybrid

5. Draw the Resonance Structures for Carbonate Ion CO₃^2-

Formal Charge References:

Reading Reference Jespersen 7^th : Section 8.7 pages 377-384

Look at Calculating formal charges on an atom in a Lewis Structure page 379.

Formula:

Jespersen’s Formula:

Look at Example 8.9 page 382-3

Try Practice Exercise 8.18; 8.19 and 8.20 page 383

Try Practice Exercise 8.21 and 8.22 Page 384

Do End of Chapter Questions #8.44-#8.47 page 397

Try Review Problems #8.105-#8.110 pages 399-400

Resonance References:

Reading Reference Jespersen 7^th : Section 8.8

Look at Example 8.8 page 385
Try Practice Exercise 8.23; 8.24 and 8.25 page 386;

Note the discussion on benzene on page 387

Answer Review questions: #8.51-#8.54 page 397

Try Review Problems: 8.113-8.118 page 400

Module 4iii - Part S: Sigma and Pi Bonds 1 point

Note Figures 9.30 and 9.31 formation of Sigma σ and Pi π Bonds !

1. Sketch the hybrid orbitals for ethane (C₂H₄) showing the 5 sigma bonds (see Figure 9.32)

2. Sketch the p-p orbital overlap in ethane (figure 9.32 page 436)

3. Sketch the hybrid orbitals for formaldehyde (CH₂O ) showing the 3 sigma bonds (see Figure 9.34)

4. Sketch the p-p orbital overlap in formaldehyde (CH₂O ) (figure 9.34 page 438)

5. Sketch the hybrid orbitals for Acetylene (C₂H₂ ) showing the 3 sigma bonds (see Figure 9.35)

6. Sketch the p-p orbital overlap in Acetylene (C₂H₂ ) (figure 9.35 page 439)

Reading Reference Jespersen 7th: Section 9.6

Note Brief Summary page 439.

Try Practice Exercises 9.20 and 9.21 page 440

Answer Review Questions # 9.30-#9.34 Page 409

Try Review Problems #9.103-#9.110