Discussion Worksheet

Instructions for Working out the Worksheets:

Work in groups of 4 on these problems. You should try to answer the questions without referring to your textbook. If you get stuck, try asking another group for help. Your TA will come around when needed to help guide you if needed.

Round Robin Instructions:

1. Each group member will be assigned a number, starting with #1 and ending with the number of people in the group.
2. Student #1 will read the question aloud and define the information needed to solve the problem, create an outline on how you can solve the problem.
3. When the group agrees that the necessary information is complete, student number two will do the first step. When the group agrees that the step is correct, student number three will do the next step. Continue this way until the group agrees that the given answer had been correctly drawn and identified.
4. Student #2 will start the next question by reading it aloud as in #1. Follow this pattern for all the questions in the session.

Topics being Covered in the Worksheet:

1. Hybridization
2. MO TheoryEnergies

1-16. In the following problems you will be working on problems to help you understand topic 1.

When atoms bon to form molecules they use molecular orbital. these are formed through the hybridization of the atomic orbitals that we have already discussed: s, p, and d orbitals.

They hybridized molecular orbital have different shapes and energy levels than the atomic orbitals. The number of molecular orbitals created by hybridization depends on the number of atomic orbitals that are mixed to form them.

In forming sp3 hybridized orbitals, four atomic orbitals are mixed, one s and three p. The energy diagram for this process is shown below. The hybridized orbitals are higher in energy than the s orbital, but lower in energy than the p orbitals, following Hund’s rule.

energy

s

p

hybridization

sp

3

# atomic orbitals hybridized orbitals

TA example: Carbon has 4 valence electrons. Add these electrons to the atomic and hybridized orbitals. This hybridization give tetrahedral geometry. With this hybridization, C will form four equivalent sigma (𝛔) bonds.

1. Draw a similar energy diagram for sp3 hybridized oxygen.
2. How many sigma bonds will be formed?
3. How are the other sp3 orbitals used?
4. Do the same for sp3 hybridized nitrogen.

In some Lewis structures, there are only three equivalent bonds formed. To create three equivalent hybridized orbitals, mix three atomic orbitals.

1. Draw and name the orbitals formed in this hybridization, then add the electrons for sulfur. Since the hybridized orbitals are close in energy, every orbital is filled with one electron before electrons are paired.

hybridization.

p

energy

s hybridization

1. The hybridized orbitals will for __________ sigma bond(s).
2. the unhybridized orbital will form _______ pi bond(s).
3. There will be _______ lone pair(s).
4. this hybridization gives what type of geometry? ________________________________
5. In linear molecules, like CO2, the central atoms have only two equivalent bonding orbitals.
6. Fill in the electrons for carbon and determine the number and typed of bonds formed. hybridization.

p energy

s hybridization

1. In CO2, determine the hybridization of the oxygen atoms. Complete the energy diagram for the oxygens. Draw the structure of CO2.

hybridization.

p

energy

s hybridization

1. In atoms with n = 3 or larger, the d orbitals can also be hybridized. In molecules with five molecular orbitals, five atomic orbitals are mixed:

_______ + _______ + _______ + _______ + _______

This will give trigonal bipyramidal geometry and is called sp3d hybridization.

1. Finally, molecules with octahedral geometry, will have ________ molecular orbitals. This hybridization is called _______________.
2. Fill in the hybridization for each of the following compounds:
 Compound Hybridization Compound Hybridization SF6 SF4 NH3 CO2 ICl4— H2O CF4 NO2— SO3 PO43—
1. Fill in the chart below for the following figures.

 atom # bond angle hybridization 1 2 3
 atom # bond angle hybridization 1 2 3

σ bonds ____

C

H

H

H

C

O

O

H

acetic acid

1

2

3

C

H

H

C

H

C

N

1

2

3

acylonitrile

π bonds _____

σ bonds ____

π bonds _____

N

C

N

C

C

C

N

C

N

H

H

C

H

H

O

C

H

H

H

O

H

C

H

H

caffeine

1

2

3

σ

bonds ___

_

π

bonds _____

 atom # bond angle hybridization 1 2 3

17-21. In the following problems you will be working on problems to help you understand topic 2. Use the MO diagrams provided. OWL goes from the 1s to 2p while we normally focus on the bonding electrons (valence electrons).

1. Refer to your MO diagrams. According to molecular orbital theory, what is the bond order for each of the following:
 a. C22— b. F22+ c. F2 d. Li2 ________ ________ ________ ________
1. Refer to the MO Diagrams. According to molecular orbital theory, which of the following lists ranks the fluorine species in terms of increasing bond order?

a. F22— < F2 < F22+ b. F22+ < F22— < F2 c. F2 < F22— < F22+ d. F2 < F22+ < F22—

1. Refer to the MO Diagrams. Use molecular orbital theory to determine if the molecular are paramagnetic or diamagnetic.
1. F2 b. B2 c. Li2 d. N2

________ ________ ________ ________

1. Refer to the MO Diagrams. Assuming that the molecular orbital energy diagram for a homonuclear diatomic molecule applies to a hero nuclear diatomic molecule, determine bond order for each below.
1. NO+ b. O22— c. NOd. C2

________ ________ ________ ________

1. Which molecule will have the following valence molecular orbital energy level diagram? σ2s2 σ*2s2 π2p4 σ2p2
1. N2 b. B2 c. O2 d. C2