Deck 16: Orbital Interactions 2: Extended Π Systems,conjugation,and Aromaticity

Question 1

Which one of the following compounds is aromatic?

A)I
B)II
C)III
D)IV
E)V

Answer 1

I

Question 2

Which atomic orbital contributor has three nodes?

A)I
B)II
C)III
D)IV
E)V

Answer 2

IV

Question 3

Which term can be used to define a molecule that is cyclic,planar,completely conjugated,and has four π electrons.

A)Aromatic
B)Antiaromatic
C)Nonaromatic
D)Semiaromatic
E)None of the above

Answer 3

Antiaromatic

Question 4

Which of the following reactions releases the least amount of heat upon hydrogenation?

A)I
B)II
C)III
D)IV
E)V

Question 5

How many of the following compounds are aromatic?

A)Zero
B)One
C)Two
D)Three
E)Four

Question 6

Assuming all of the following molecules are planar,which one can be labeled antiaromatic?

A)I
B)II
C)III
D)IV
E)V

Question 7

Which molecular orbital has the lowest energy?

A)The highest bonding MO
B)The highest antibonding MO
C)The lowest bonding MO
D)HOMO
E)LUMO

Question 8

Assume that a compound is a cyclic,planar,completely conjugated ring.Which number of π electrons would make it aromatic?

A)0 π electrons
B)2 π electrons
C)3 π electrons
D)4 π electrons
E)32 π electrons

Question 9

Which atomic orbital contributor has three areas of constructive interference?

A)I
B)II
C)III
D)IV
E)V

Question 10

Which hydrogen has the lowest Pk_a?

A)H_A
B)H_B
C)H_C
D)H_D
E)H_E

Question 11

Which of the following molecules is aromatic?

A)I
B)II
C)III
D)IV
E)V

Question 12

Which number of π electrons can be defined as an anti-Hückel number?

A)0
B)1
C)2
D)3
E)22

Question 13

Which of the following molecules is aromatic?

A)I
B)II
C)III
D)IV
E)V

Question 14

Which atomic orbital contributor corresponds to the HOMO of a molecule with four π electrons in a conjugated system?

A)I
B)II
C)III
D)IV
E)V

Question 15

Which atomic orbital contributor has the highest energy?

A)I
B)II
C)III
D)IV
E)V

Question 16

How many areas of constructive overlap are in the following atomic orbital contributor?

A)Zero
B)One
C)Two
D)Three
E)Four

Question 17

Which atomic orbital contributor has the lowest energy?

A)I
B)II
C)III
D)IV
E)V

Question 18

Assuming all of the following molecules are planar,which one can be labeled antiaromatic?

A)I
B)II
C)III
D)IV
E)V

Question 19

Which of the following reactions releases the least amount of heat upon hydrogenation?

A)I
B)II
C)III
D)IV
E)V

Question 20

Which of the following molecules is aromatic?

A)I
B)II
C)III
D)IV
E)V

Question 21

How many electrons are in the following molecule's largest conjugated π system?

A)Two
B)Four
C)Six
D)Eight
E)Ten

Question 22

Rank the three following molecules by the amount of heat released upon hydrogenation (from lowest amount to highest amount).Explain your answer.

Question 23

Which hydrogen has the lowest Pk_a?

A)H_A
B)H_B
C)H_C
D)H_D
E)H_E

Question 24

Rank the three following molecules by the amount of heat released upon hydrogenation (from lowest amount to highest amount).Explain your answer.

Question 25

Use the Frost method to explain whether furan,diagramed below is aromatic,antiaromatic,or nonaromatic.In your Frost diagram,fill in all π electrons,and label the HOMO and the LUMO.

Question 26

Is the following compound aromatic,antiaromatic,or nonaromatic? Explain your answer.

Question 27

Give the four requirements a molecule must have to be considered aromatic.

Question 28

Identify the areas of constructive interference for the following atomic contributor.

Question 29

Which heterolysis step will occur slowest?

A)I
B)II
C)III
D)IV
E)V

Question 30

How many nodes does the following atomic contributor have?

Question 31

Identify the areas of constructive interference for the following atomic contributor.

Question 32

Assume that the following molecule is planar.Use the Frost method to explain whether it is aromatic,antiaromatic,or nonaromatic.In your Frost diagram,fill in all π electrons,and label the HOMO and the LUMO.

Question 33

How many nodes does the following atomic contributor have?

Question 34

How many electrons are in the given molecule's largest conjugated π system?

A)Four
B)Five
C)Six
D)Eight
E)Ten

Question 35

For the following molecule,give the number of π electrons and nonbonding electrons.

Question 36

How many electrons are in the following molecule's largest conjugated π system?

A)Two
B)Four
C)Six
D)Eight
E)Ten

Question 37

Is the following compound aromatic,antiaromatic,or nonaromatic? Explain your answer.

Question 38

How many electrons are in the following molecule's largest conjugated π system?

A)Two
B)Four
C)Six
D)Eight
E)Ten

Question 39

Which heterolysis step will occur fastest?

A)I
B)II
C)III
D)IV
E)V

Question 40

Is the following compound aromatic,antiaromatic,or nonaromatic? Explain your answer.

Question 41

Assume that the following molecule is planar.Use the Frost method to explain whether it is aromatic,antiaromatic,or nonaromatic.In your Frost diagram,fill in all π electrons,and label the HOMO and the LUMO.

Question 42

Is the following compound aromatic,antiaromatic,or nonaromatic? Explain your answer.

Question 43

Is the following compound aromatic,antiaromatic,or nonaromatic? Explain your answer.

Question 44

Is the following compound aromatic,antiaromatic,or nonaromatic? Explain your answer.

Question 45

How many different π systems does the following molecule contain?

Question 46

For the following molecule,give the number of π electrons and the number of nonbonding electrons.

Question 47

Is the following compound aromatic,antiaromatic,or nonaromatic? Explain your answer.

Question 48

Which is more acidic,H_A or H_B? Explain.

Question 49

Is the following compound aromatic,antiaromatic,or nonaromatic? Explain your answer.

Question 50

Assume that the following molecule is planar.Use the Frost method to explain whether it is aromatic,antiaromatic,or nonaromatic.In your Frost diagram,fill in all π electrons,and label the HOMO and the LUMO.

Question 51

Which is more acidic,H_A or H_B? Explain.

Question 52

Is the following compound aromatic,antiaromatic,or nonaromatic? Explain your answer.

Question 53

How many different π systems does the following molecule contain? Give the number of electrons in each.

Question 54

Assume that the following molecule is planar.Use the Frost method to explain whether it is aromatic,antiaromatic,or nonaromatic.In your Frost diagram,fill in all π electrons,and label the HOMO and the LUMO.