Deck 5: Orbital Interactions 1: Hybridization and Two-Center Molecular Orbitals

Question 1

What abbreviation is used to designate the molecular orbital of highest energy that is occupied with electrons?

A)MOHE
B)HOME
C)HOMO
D)HAHA
E)LUMO

Answer 1

HOMO

Question 2

Which two atomic orbitals overlap to form the MOs of σ symmetry that correspond to the CC bond in ethylene?

A)2s and 2p
B)2p and sp²
C)sp² and sp²
D)sp³ and sp³
E)2p and 2p

Answer 2

sp² and sp²

Question 3

Which CC bond in the molecule below is formed from overlap of an sp³ orbital and an sp² orbital?

A)The C₁C₂ σ bond
B)The C₁C₂ π bond
C)The C₃C₄ σ bond
D)The C₃C₄ π bond
E)The C₄C₅ σ bond

Answer 3

The C₃C₄ σ bond

Question 4

Which CC bond in the molecule below is formed from overlap of two 2p orbitals?

A)The C₁C₂ σ bond
B)The C₁C₂ π bond
C)The C₃C₄ σ bond
D)The C₃C₄ π bond
E)The C₄C₅ σ bond

Question 5

Which CC bond in the molecule below is formed from overlap of two sp²-hybridized orbitals?

A)The C₆C₇ σ bond
B)The C₇ C₈ σ bond
C)The C₅C₆ σ bond
D)The C₄C₅ π bond
E)The C₄C₅ σ bond

Question 6

Boat A follows Boat B across a lake,keeping a safe distance.The waves generated by the two boats meet to create a new wave that is unusually large.What chemical concept explains the formation of the larger wave?

A)Destructive interference occurs.
B)Constructive interference occurs.
C)Molecular orbital interference occurs.
D)The Heisenberg uncertainty principle dominates.
E)Hund's rule plays a role.

Question 7

Which two carbon atoms participate in the strongest σ bond?

A)C₁C₂
B)C₂C₃
C)C₃C₄
D)C₄C₅
E)C₇C₈

Question 8

Which of the following statements about molecular orbital theory are true?
I. According to MO theory,electrons are localized on specific atoms.
II.The linear combination of atomic orbitals method is used to generate molecular orbitals for a molecule.
III. The number of molecular orbitals created from the LCAO approach is identical to the number of atomic orbitals that were originally combined.
IV. Molecular orbital theory is a powerful bonding theory that accurately predicts structures of complex molecules.
V. The MOs generated are classified as either bonding,nonbonding,or antibonding.

A)Only II, III, and IV are true.
B)Only III, IV, and V are true.
C)Only IV and V are true.
D)All choices except I are true.
E)All choices are true.

Question 9

Which characteristics describe the bonding MO for the weakest individual covalent bond in ethene,C₂H₄?
I. The MO possesses π symmetry.
II.The MO possesses σ symmetry.
III.The MO can be called the HOMO.
IV.The MO can be called the LUMO.
V.The MO contains two electrons of opposing spin.

A)All of the choices
B)II, III, and V
C)II and V
D)I and V
E)I, III, and V

Question 10

According to valence bond theory,which atomic orbitals of carbon may be hybridized to account for bonding? Why?

A)1s, 2s, and 2p orbitals all may hybridize; these orbitals are of the same phase.
B)Only 2p orbitals may hybridize; the 2p orbital is carbon's highest-energy atomic orbital.
C)Only 1s and 2s orbitals of carbon may hybridize; each contains electrons to share in bonding.
D)Only 2s and 2p may hybridize; these orbitals contain valence electrons used in bonding.
E)Only 2s orbitals may hybridize; these orbitals contain valence electrons.

Question 11

Which two carbon atoms participate in the longest σ bond?

A)C₁C₂
B)C₂C₃
C)C₃C₄
D)C₄C₅
E)C₇C₈

Question 12

Naltrexone is an antagonist at the mu opioid receptor.What is the hybridization state and geometry of the nitrogen atom in naltrexone?

A)sp hybridized and linear geometry
B)sp² hybridized and trigonal pyramidal
C)sp³ hybridized and trigonal pyramidal
D)sp³ hybridized and trigonal planar
E)sp³ hybridized and bent

Question 13

Which of the following functional groups has a lone pair residing in an sp-hybridized orbital?

A)Amide
B)Alkyne
C)Amine
D)Nitrile
E)Ester

Question 14

An atom's electrons have a high probability of being found within a region of three-dimensional space defined by quantum mechanics.What term identifies this region?

A)Electron configuration
B)Atomic orbital
C)Central core
D)Nucleus
E)Valence shell

Question 15

Which of the following structures contains an sp²-hybridized oxygen atom because a lone pair on oxygen is delocalized via resonance?

A)Structure I
B)Structure II
C)Structures II and V
D)Structure IV
E)Structures I and IV

Question 16

Which functional group has two sp²-hybridized oxygen atoms within its structure,yet cannot be a H-bond donor?

A)Amide
B)Alcohol
C)Ester
D)Ketone
E)Aldehyde

Question 17

Boat A and Boat B start on opposite sides of a lake.The boats cross the lake heading directly toward one another at equal rates of speed.Upon meeting,what happens to the waves generated by the two boats?

A)Destructive interference occurs, and thus the waves negate each other, leaving only a ripple.
B)Constructive interference occurs, and thus the new wave formed is larger in size.
C)The Heisenberg uncertainty principle dominates, and thus the outcome of the meeting of the two waves is not concrete.
D)Destructive interference occurs, forming one wave that is much larger in size.
E)Constructive interference occurs, forming one wave that is much larger in size.

Question 18

From left to right,identify the hybridization of the three carbon atoms in the interesting organic structure below.These interesting structures are called cumulenes.

A)sp³, sp², sp³
B)sp³, sp, sp³
C)sp², sp, sp²
D)sp, sp, sp²
E)sp², sp², sp²

Question 19

What abbreviation is used to designate the lowest-energy molecular orbital for a molecule that is devoid of electrons?

A)MOLE
B)LUMO
C)LEMO
D)NEMO
E)MOWO

Question 20

Rank the highlighted σ bonds in order of decreasing length.

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

Question 21

How many total electrons reside in molecular orbitals of π symmetry for this molecule?

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

Question 22

Select which of the following molecules have two distinct configurations about the double bond.

A)All of these
B)All of these except IV
C)All of these except III
D)I and II only
E)II and III only

Question 23

An alkene contains a double bond.Why is the C
C of an alkene rigid and unable to freely rotate?

A)The C C bond is very strong, and it is impossible to break it.
B)The σ bond gets blocked by the hydrogen atoms.
C)The sp² hybrid orbitals of carbon take up too much room.
D)The π electrons are delocalized through the σ bonds.
E)The 2p orbitals of the π bond overlap above and below the C C plane to restrict rotation.

Question 24

Given below are 2s,2p,sp,sp²,and sp³ orbitals,all drawn to scale and in no particular order.Which of these orbitals exhibits 50% s character?

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

Question 25

One of the following statements about the relationship of % s character to organic structure is false.Identify which statement is false.

A)The % s character and effective electronegativity are directly proportional to one another.
B)An sp³ orbital has greater % s character than an sp² orbital.
C)Two orbitals with high % s character will form a stronger bond.
D)A 2s orbital has greater s character than any of the hybrid orbitals.
E)An orbital with greater % s character is smaller and more compact.

Question 26

Rank the carbon atoms in order of increasing percent s orbital character.

A)I < II < III
B)I < III < II
C)II < III < I
D)II < I < III
E)III < II < I

Question 27

For one or more of the following molecules,(1)two distinct configurations about the double bond are possible,and (2)the -OH and -Br are trans.Select the molecule or molecules that fit this description.

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

Question 28

Given below are 2s,2p,sp,sp²,and sp³ orbitals,all drawn to scale and in no particular order.Which of these orbitals represents the hybrid orbital with the lowest effective electronegativity?

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

Question 29

Given below are 2s,2p,sp,sp²,and sp³ orbitals,all drawn to scale and in no particular order.Which of these orbitals would carbon use in the CO σ bond of acetone?

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

Question 30

Given below are 2s,2p,sp,sp²,and sp³ orbitals,all drawn to scale and in no particular order.Which of these orbitals represents the hybrid orbital with the greatest effective electronegativity?

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

Question 31

Styrene is an important industrial chemical in the generation of various plastics.Determine how many bonding molecular orbitals are created during the LCAO process to accommodate the π electrons in styrene.

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

Question 32

How many π bonds are present in the molecule below?

A)Three
B)Four
C)Five
D)Six
E)Seven

Question 33

Given below are 2s,2p,sp,sp²,and sp³ orbitals,in random order.Which of these orbitals exhibits 33% s character?

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

Question 34

For one or more of the following molecules,two distinct configurations about the double bond are possible,and the two alkyl substituents are trans.Select the molecule or molecules that fit this description.

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

Question 35

Rank the carbon atoms in order of increasing effective electronegativity.

A)I < II < III
B)I < III < II
C)II < III < I
D)II < I < III
E)III < II < I

Question 36

For the given molecule,an amino alcohol,how many electrons are present in nonbonding molecular orbitals?

A)Seven
B)Six
C)Five
D)Four
E)Three

Question 37

Given below are 2s,2p,sp,sp²,and sp³ orbitals,all drawn to scale and in no particular order.Which of these orbitals would carbon use for a CO π bond?

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

Question 38

Which two atomic orbitals overlap to form the MOs of σ symmetry that correspond to a CH bond in ethylene?

A)An sp² orbital from both C and H
B)A 2p orbital from C and an sp² orbital from H
C)A 1s orbital of H and the sp² orbital of C
D)A 2s orbital of H and the sp² orbital of C
E)A 2p orbital from both C and H

Question 39

What is the geometry and hybridization of the central carbon atom in the cumulene below?

A)sp³ hybridized and tetrahedral
B)sp³ hybridized and trigonal pyramidal
C)sp² hybridized and trigonal planar
D)sp² hybridized and bent
E)sp hybridized and linear

Question 40

Which two atomic orbitals overlap to form the bonding and antibonding MOs of π symmetry for ethylene,C₂H₄?

A)2s and 2p
B)2p and sp²
C)sp² and sp²
D)sp³ and sp³
E)2p and 2p

Question 41

Bioymifi is a novel small molecule that selectively triggers programmed cell death in certain cancer cells.Identify the following structural features in Bioymifi: (a)phenyl ring,(b)a lone pair found in a 2p orbital that can be delocalized three different ways,(c)an sp²-hybridized oxygen whose lone pairs are not delocalized,(d)an sp²-hybridized oxygen whose lone pairs are delocalized,(e)a nitrogen with bent geometry,and (f)a nitrogen with trigonal planar geometry.

Question 42

Amide bonds join amino acids together to make proteins.Sketch an orbital picture of the amide functional group given below.Identify the orbitals from each atom that are used to form the σ and π bonds in the given amide.Which orbitals house the lone pairs on N and O?

Question 43

Tubulysin D is a peptide-based marine natural product with biological activity.Identify the following structural features of tubulysin D.
(a) Place a box around any sp³ nitrogen.
(b) Star (*)any oxygen atom that has two oxygen lone pairs in sp²-hybridized orbitals.
(c) Place a number symbol (#)on any oxygen atom that is sp² hybridized as a consequence of having a lone pair in a 2p orbital.
(d) Use an arrow to point to any N atom that has trigonal planar geometry.

Question 44

Why is a σ bond formed from the overlap of two sp² orbitals stronger than one formed from the end-on-end overlap of two p orbitals?

Question 45

Using line structures,deduce individual resonance contributors from the resonance hybrid structure given here.Identify any lone pairs that are localized,rather than delocalized.Based on orbital hybridization theory,what orbitals accommodate these lone pairs?

Question 46

Draw line structures of a molecule with the formula C₄H₆O that has the characteristics outlined in (a),(b),and (c)below.
(a)Two sp-hybridized carbon atoms,a methyl group,and a primary alcohol
(b)An epoxide and one carbon-carbon bond formed from the overlap of 2p orbitals
(c)A cyclopropane ring connected to only one substituent via a σ bond.This σ bond is formed from overlap of one Csp³ and one Csp² orbital.

Question 47

Acetonitrile,C₂H₃N,is a polar aprotic solvent commonly used in organic reactions.Draw the structure of acetonitrile.Determine the number of σ bonds,the number of π bonds,and the number of electrons occupying nonbonding MOs for the molecule.

Question 48

Sketch an orbital picture of ethylene,H₂C
CH₂,and highlight the orbitals that overlap to form each σ and π bond.Identify the orbitals from each atom that overlap to form the σ and π bonds.Why is the CC π bond weaker than the CC σ bond? Use orbital structure as part of your explanation.

Question 49

Formaldehyde,CH₂O,is a biological preservative and the simplest aldehyde.Draw the structure of formaldehyde.Determine the number of σ bonds,the number of π bonds,and the number of electrons occupying nonbonding MOs for formaldehyde.

Question 50

Draw line structures of a molecule with the formula C₅H₁₁N that has the characteristics outlined in (a),(b),and (c)below.
(a) An sp² nitrogen atom with a conjugated lone pair,one methyl substituent,and one ethyl substituent
(b) A disubstituted trans alkene and a primary amine with an sp³ nitrogen connected to an sp³ carbon
(c) A three-membered ring containing a secondary sp³ nitrogen with cis methyl and ethyl substituents on the ring

Question 51

The molecule benzene,which features a conjugated ring system,has interesting properties.In fact,extended benzene-like molecules are key features of many drug classes,including DNA intercalators.
(a) Draw an energy-based electron configuration diagram for any one carbon atom in benzene.Clearly show which orbitals are hybridized and which orbital is used for the π bond.
(b) Next,consider the π MO diagram of benzene generated via the LCAO method.Add π electrons to the diagram,and label each orbital as π bonding MO or π* antibonding MO.How many total electrons reside in MOs of π symmetry for benzene?

Question 52

Use your knowledge of hybridization to fill in the table below.Rank the sigma bonds labeled A,B,C,and D from strongest to weakest.Explain your answer.

Question 53

Compare the p orbital orientation and overlap needed to form a σ bond and a π bond.Using an example,create a diagram for each type of bond,and differentiate between σ and π bond characteristics.

Question 54

Consider the hybrid structure below and the labeling scheme provided.Draw the most stable resonance contributor.Identify the hybridization and VSEPR geometry of each atom.

Question 55

Tropyllium bromide is an ionic organic compound that is soluble in water but not in diethyl ether.What is the hybridization of the positively charged carbon in tropyllium bromide? Do you expect the carbon framework to be planar? Justify your response using an orbital diagram.

Question 56

Below are two reasonable acyclic structures for ozone,O₃,that differ in π electron delocalization.Identify the hybridization of all the oxygen atoms in ozone for each individual resonance contributor.What is the geometry of the central oxygen in each structure?