Question 1

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

Accepted Answer

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 F1F1F1S1F1F1F10F1F1F1S1F1F1F10C plane to restrict rotation. 
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 F1F1F1S1F1F1F10F1F1F1S1F1F1F10C plane to restrict rotation.

Question 2

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.

Accepted Answer

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. 
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 3

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

Accepted Answer

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

Question 4

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.

Accepted Answer

Question 5

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

Accepted Answer

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 
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 6

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

Accepted Answer

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. 
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 7

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

Accepted Answer

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 
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 8

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

Accepted Answer

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

Question 9

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?

Accepted Answer

@#IMG-DLM& The sp³ oxygen of the ether us

Question 10

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

Accepted Answer

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

Question 11

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.

Accepted Answer

Question 12

Which CF1F1F1S1F1F1F10F1F1F1S1F1F1F10F1F1F1S1F1F1F10C bond in the molecule below is formed from overlap of two sp2-hybridized orbitals?

Accepted Answer

A) The C6F1F1F1S1F1F1F10F1F1F1S1F1F1F10F1F1F1S1F1F1F10C7 σ bond 
B) The C7 F1F1F1S1F1F1F10F1F1F1S1F1F1F10C8 σ bond 
C) The C5F1F1F1S1F1F1F10F1F1F1S1F1F1F10F1F1F1S1F1F1F10C6 σ bond 
D) The C4F1F1F1S1F1F1F10F1F1F1S1F1F1F10F1F1F1S1F1F1F10C5 π bond 
E) The C4F1F1F1S1F1F1F10F1F1F1S1F1F1F10F1F1F1S1F1F1F10C5 σ bond 
A) The C6F1F1F1S1F1F1F10F1F1F1S1F1F1F10F1F1F1S1F1F1F10C7 σ bond 
B) The C7 F1F1F1S1F1F1F10F1F1F1S1F1F1F10C8 σ bond 
C) The C5F1F1F1S1F1F1F10F1F1F1S1F1F1F10F1F1F1S1F1F1F10C6 σ bond 
D) The C4F1F1F1S1F1F1F10F1F1F1S1F1F1F10F1F1F1S1F1F1F10C5 π bond 
E) The C4F1F1F1S1F1F1F10F1F1F1S1F1F1F10F1F1F1S1F1F1F10C5 σ bond

Question 13

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.

Accepted Answer

The strongest bond is B; the w

Question 14

Rank the highlighted σ bonds in order of decreasing length.

Accepted Answer

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 
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 15

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.

Accepted Answer

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

Question 16

How many π bonds are present in the molecule below?

Accepted Answer

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

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

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

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

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.

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

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

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

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

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?

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

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

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.

Rank the highlighted σ bonds in order of decreasing length.

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.

How many π bonds are present in the molecule below?

Atomic and Molecular Structure

Interchapter: Nomenclature 1-4

Interchapter 1molecular Orbital Theory and Chemical Reactions

Three-Dimensional Geometry,intermolecular Interactions,and Physical Properties

Isomerism 1: Conformational and Constitutional Isomers

Isomerism 2: Chirality,enantiomers,and Diastereomers

The Proton Transfer Reaction: an Introduction to Mechanisms,thermodynamics,and Charge Stability

An Overview of the Most Common Elementary Steps

An Introduction to Multistep Mechanisms: Sn1 and E1 Reactions

Nucleophilic Substitution and Elimination Reactions 1: Competition Among Sn2,sn1,e2,and E1 Reactions

Nucleophilic Substitution and Elimination Reactions 2: Reactions That Are Useful for Synthesis

Electrophilic Addition to Nonpolar Π Bonds 1: Addition of a Brønsted Acid

Electrophilic Addition to Nonpolar Π Bonds 2: Reactions Involving Cyclic Transition States

Organic Synthesis 1: Beginning Concepts

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

Structure Determination 1: Ultravioletvisible and Infrared Spectroscopies

Structure Determination 2: Nuclear Magnetic Resonance Spectroscopy and Mass Spectrometry

Nucleophilic Addition to Polar Π Bonds 1: Addition of Strong Nucleophiles

Nucleophilic Addition to Polar Π Bonds 2: Addition of Weak Nucleophiles and Acid and Base Catalysis

Organic Synthesis 2: Intermediate Topics in Synthesis Design,and Useful Reduction and Oxidation Reactions

Nucleophilic Additionelimination Reactions 1: the General Mechanism Involving Strong Nucleophiles

Nucleophilic Additionelimination Reactions 2: Weak Nucleophiles

Electrophilic Aromatic Substitution 1: Substitution on Benzene; Useful Accompanying Reactions

Electrophilic Aromatic Substitution 2: Substitution on Mono- and Disubstituted Benzene and Other Aromatic Rings

The Dielsalder Reaction and Other Pericyclic Reactions

Reactions Involving Free Radicals

Polymers

Filters

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.

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

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