Question 1

Which electron-pair geometry corresponds to a steric number of 3?

Accepted Answer

A) linear 
B) trigonal planar 
C) tetrahedral 
D) trigonal bipyramidal 
E) octahedral 
A) linear 
B) trigonal planar 
C) tetrahedral 
D) trigonal bipyramidal 
E) octahedral

Question 2

Which statement A-D about sigma (F1F1F1S1F1F1F10) and pi (F1F1F1S1F1F1F10) bonds is not correct?

Accepted Answer

A) A sigma bond has the region of high electron density aligned along the bond axis, which is the line connecting the two atoms. 
B) A pi bond has regions of high electron density lying above and below the bond axis, which is the line connecting the two atoms. 
C) A pi bond commonly is formed from the overlap of two unhybridized atomic 2p orbitals. 
D) In the trigonal planar geometry, the sigma bonds are formed from the overlap of an sp2 hybridized orbital with another orbital. 
E) Statements A-D are all correct. 
A) A sigma bond has the region of high electron density aligned along the bond axis, which is the line connecting the two atoms. 
B) A pi bond has regions of high electron density lying above and below the bond axis, which is the line connecting the two atoms. 
C) A pi bond commonly is formed from the overlap of two unhybridized atomic 2p orbitals. 
D) In the trigonal planar geometry, the sigma bonds are formed from the overlap of an sp2 hybridized orbital with another orbital. 
E) Statements A-D are all correct.

Question 3

Draw the band gap profile for a) the semiconductor Si, b) n-doped Si, and c) p-doped Si. Briefly describe how n- and p-doping enhance conductivity.

Accepted Answer

With pure Si (in a), there is a large en

Question 4

Which statement about a semiconductor is not correct?

Accepted Answer

A) Both electrons in the conduction band and holes in the valence band conduct electricity. 
B) The band gap becomes smaller with increasing temperature. 
C) The band gap is smaller than in an insulator. 
D) Adding an impurity can increase the conductivity. 
E) Conductivity increases with increasing temperature. 
A) Both electrons in the conduction band and holes in the valence band conduct electricity. 
B) The band gap becomes smaller with increasing temperature. 
C) The band gap is smaller than in an insulator. 
D) Adding an impurity can increase the conductivity. 
E) Conductivity increases with increasing temperature.

Question 5

Which of the following elements are semiconductors? C, Si, Ge, Sn

Accepted Answer

A) C and Si only 
B) Si and Ge only 
C) Ge and Sn only 
D) None of these elements are semiconductors unless a dopant is added. 
E) All of these elements are semiconductors. 
A) C and Si only 
B) Si and Ge only 
C) Ge and Sn only 
D) None of these elements are semiconductors unless a dopant is added. 
E) All of these elements are semiconductors.

Question 6

What is the hybridization of the carbon atom in CS2?

Accepted Answer

A) sp3 
B) sp3d 
C) sp3d 2 
D) sp 
E) sp2 
A) sp3 
B) sp3d 
C) sp3d 2 
D) sp 
E) sp2

Question 7

What is the bond order of B2?

Accepted Answer

A) 0 
B) 1 
C) 2 
D) 3 
E) 1.5 
A) 0 
B) 1 
C) 2 
D) 3 
E) 1.5

Question 8

Which of the following has a local molecular geometry about a carbon atom that is trigonal planar?

Accepted Answer

A) CH3CH2OH 
B) CH3OH 
C) C2H4 
D) CH3OCH3 
E) C2H2 
A) CH3CH2OH 
B) CH3OH 
C) C2H4 
D) CH3OCH3 
E) C2H2

Question 9

Which of the following molecules or ions is not polar?

Accepted Answer

A) O3 
B) H2O 
C) SO2 
D) I3F1F1F1S1F1F1F10 
E) S3 
A) O3 
B) H2O 
C) SO2 
D) I3F1F1F1S1F1F1F10 
E) S3

Question 10

What is the bond order of C2?

Accepted Answer

A) 0 
B) 1 
C) 2 
D) 3 
E) 1.5 
A) 0 
B) 1 
C) 2 
D) 3 
E) 1.5

Question 11

Use energy levels of diatomic molecules derived from molecular orbital theory to predict the magnetic properties of F2 and the dication F22F1F1F1S1F1F1F10.

Accepted Answer

A) F2 (paramagnetic); F22F1F1F1S1F1F1F10 (paramagnetic) 
B) F2 (paramagnetic); F22F1F1F1S1F1F1F10 (diamagnetic) 
C) F2 (diamagnetic); F22F1F1F1S1F1F1F10 (paramagnetic) 
D) F2 (diamagnetic); F22F1F1F1S1F1F1F10 (diamagnetic) 
E) Neither have magnetic properties; only metals have magnetic properties. 
A) F2 (paramagnetic); F22F1F1F1S1F1F1F10 (paramagnetic) 
B) F2 (paramagnetic); F22F1F1F1S1F1F1F10 (diamagnetic) 
C) F2 (diamagnetic); F22F1F1F1S1F1F1F10 (paramagnetic) 
D) F2 (diamagnetic); F22F1F1F1S1F1F1F10 (diamagnetic) 
E) Neither have magnetic properties; only metals have magnetic properties.

Question 12

The molecular orbital description for metal bonding is different from that for diatomic molecules in that ________

Accepted Answer

A) there are no antibonding orbitals in the metal bonding description. 
B) quantum theory no longer applies as the orbitals are continuous. 
C) the orbitals are so close in energy that they are referred to as bands. 
D) the increased number of electrons results in each bond being stronger. 
E) All of the above are true. 
A) there are no antibonding orbitals in the metal bonding description. 
B) quantum theory no longer applies as the orbitals are continuous. 
C) the orbitals are so close in energy that they are referred to as bands. 
D) the increased number of electrons results in each bond being stronger. 
E) All of the above are true.

Question 13

Which of the following molecules or ions has a linear molecular geometry?

Accepted Answer

A) H2O 
B) H2S 
C) ICl3 
D) I3- 
E) SO2 
A) H2O 
B) H2S 
C) ICl3 
D) I3- 
E) SO2

Question 14

What is the valence electron molecular orbital electron configuration of F2?

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 15

Which of the following has a central atom with the same hybridization as the carbon in formaldehyde (CH2O)?

Accepted Answer

A) SO2 
B) OCS 
C) ICl3 
D) I3F1F1F1S1F1F1F10 
E) C2H2 
A) SO2 
B) OCS 
C) ICl3 
D) I3F1F1F1S1F1F1F10 
E) C2H2

Question 16

Which type of molecular orbital is used to describe a buildup of electron density along the axis connecting two atomic nuclei to form a bond?

Accepted Answer

A) (F1F1F1S1F1F1F10) 
B) (F1F1F1S1F1F1F10) 
C) (F1F1F1S1F1F1F10*) 
D) (F1F1F1S1F1F1F10*) 
E) (py) 
A) (F1F1F1S1F1F1F10) 
B) (F1F1F1S1F1F1F10) 
C) (F1F1F1S1F1F1F10*) 
D) (F1F1F1S1F1F1F10*) 
E) (py)

Question 17

Which statement regarding the electronic structure of solids is not correct?

Accepted Answer

A) The band theory of solids is like molecular orbital theory in that the electronic wave function is delocalized to some extent over all the constituent atoms. 
B) In solids that are electrical insulators, there is a large gap between a filled valence band and a vacant conduction band. 
C) In semiconductors, the gap between the valence band and conduction band is small, so a few electrons have sufficient thermal energy to be found in the conduction band. 
D) NF1F1F1S1F1F1F10 and p-type semiconductors can be produced by doping a semimetal with an element from a different group. 
E) Germanium doped with arsenic is a p-type semiconductor. 
A) The band theory of solids is like molecular orbital theory in that the electronic wave function is delocalized to some extent over all the constituent atoms. 
B) In solids that are electrical insulators, there is a large gap between a filled valence band and a vacant conduction band. 
C) In semiconductors, the gap between the valence band and conduction band is small, so a few electrons have sufficient thermal energy to be found in the conduction band. 
D) NF1F1F1S1F1F1F10 and p-type semiconductors can be produced by doping a semimetal with an element from a different group. 
E) Germanium doped with arsenic is a p-type semiconductor.

Question 18

Consider the molecule below-how many sp2 hybridized carbon atoms are present in the compound?

Accepted Answer

A) 4 
B) 6 
C) 3 
D) 5 
E) 7 
A) 4 
B) 6 
C) 3 
D) 5 
E) 7

Question 19

The bond angle in a trigonal planar structure is ________

Accepted Answer

A) 90F1F1F1S1F1F1F10. 
B) 180F1F1F1S1F1F1F10. 
C) 109.5F1F1F1S1F1F1F10. 
D) 120F1F1F1S1F1F1F10. 
E) 105F1F1F1S1F1F1F10. 
A) 90F1F1F1S1F1F1F10. 
B) 180F1F1F1S1F1F1F10. 
C) 109.5F1F1F1S1F1F1F10. 
D) 120F1F1F1S1F1F1F10. 
E) 105F1F1F1S1F1F1F10.

Question 20

What is the valence electron molecular orbital electron configuration of the O2F1F1F1S1F1F1F10 anion?

Accepted Answer

A) (F1F1F1S1F1F1F102s)2(F1F1F1S1F1F1F10*2s)2(F1F1F1S1F1F1F102p)4(F1F1F1S1F1F1F10 2p)2(F1F1F1S1F1F1F10 *2p)2(F1F1F1S1F1F1F10*2p)1 
B) (F1F1F1S1F1F1F102s)2(F1F1F1S1F1F1F10*2s)2(F1F1F1S1F1F1F102p)6(F1F1F1S1F1F1F10*2p)1 
C) (F1F1F1S1F1F1F102s)2(F1F1F1S1F1F1F10*2s)2(F1F1F1S1F1F1F10 2p)2(F1F1F1S1F1F1F102p)6(F1F1F1S1F1F1F10*2p)1 
D) (F1F1F1S1F1F1F102s)2(F1F1F1S1F1F1F10*2s)2(F1F1F1S1F1F1F10 2p)2(F1F1F1S1F1F1F102p)4(F1F1F1S1F1F1F10*2p)3 
E) (F1F1F1S1F1F1F102s)2(F1F1F1S1F1F1F10*2s)2(F1F1F1S1F1F1F10 2p)2(F1F1F1S1F1F1F102p)4(F1F1F1S1F1F1F10 *2p)2(F1F1F1S1F1F1F10*2p)1 
A) (F1F1F1S1F1F1F102s)2(F1F1F1S1F1F1F10*2s)2(F1F1F1S1F1F1F102p)4(F1F1F1S1F1F1F10 2p)2(F1F1F1S1F1F1F10 *2p)2(F1F1F1S1F1F1F10*2p)1 
B) (F1F1F1S1F1F1F102s)2(F1F1F1S1F1F1F10*2s)2(F1F1F1S1F1F1F102p)6(F1F1F1S1F1F1F10*2p)1 
C) (F1F1F1S1F1F1F102s)2(F1F1F1S1F1F1F10*2s)2(F1F1F1S1F1F1F10 2p)2(F1F1F1S1F1F1F102p)6(F1F1F1S1F1F1F10*2p)1 
D) (F1F1F1S1F1F1F102s)2(F1F1F1S1F1F1F10*2s)2(F1F1F1S1F1F1F10 2p)2(F1F1F1S1F1F1F102p)4(F1F1F1S1F1F1F10*2p)3 
E) (F1F1F1S1F1F1F102s)2(F1F1F1S1F1F1F10*2s)2(F1F1F1S1F1F1F10 2p)2(F1F1F1S1F1F1F102p)4(F1F1F1S1F1F1F10 *2p)2(F1F1F1S1F1F1F10*2p)1

Exam 9: Molecular Geometry: Shape Determines Function

Which electron-pair geometry corresponds to a steric number of 3?

Which statement A-D about sigma () and pi () bonds is not correct?

Draw the band gap profile for a) the semiconductor Si, b) n-doped Si, and c) p-doped Si. Briefly describe how n- and p-doping enhance conductivity.

Which statement about a semiconductor is not correct?

Which of the following elements are semiconductors? C, Si, Ge, Sn

What is the hybridization of the carbon atom in CS2?

What is the bond order of B2?

Which of the following has a local molecular geometry about a carbon atom that is trigonal planar?

Which of the following molecules or ions is not polar?

What is the bond order of C2?

Use energy levels of diatomic molecules derived from molecular orbital theory to predict the magnetic properties of F2 and the dication F22.

The molecular orbital description for metal bonding is different from that for diatomic molecules in that ________

Which of the following molecules or ions has a linear molecular geometry?

What is the valence electron molecular orbital electron configuration of F2?

Which of the following has a central atom with the same hybridization as the carbon in formaldehyde (CH2O)?

Which type of molecular orbital is used to describe a buildup of electron density along the axis connecting two atomic nuclei to form a bond?

Which statement regarding the electronic structure of solids is not correct?

Consider the molecule below-how many sp2 hybridized carbon atoms are present in the compound?

The bond angle in a trigonal planar structure is ________

What is the valence electron molecular orbital electron configuration of the O2 anion?

Matter and Energy: The Origin of the Universe

Atoms, Ions, and Molecules: Matter Starts Here

Stoichiometry: Mass, Formulas, and Reactions

Solution Chemistry: The Hydrosphere

Thermochemistry: Energy Changes in Reactions

Properties of Gases: The Air We Breathe

A Quantum Model of Atoms: Waves and Particles

Chemical Bonds: What Makes a Gas a Greenhouse Gas

Intermolecular Forces: The Uniqueness of Water

Solutions: Properties and Behavior

Solids: Crystals, Alloys, and Polymers

Chemical Kinetics: Reactions in the Atmosphere

Chemical Equilibrium: How Much Product Does a Reaction Really Make

Acidbase Equilibria: Proton Transfer in Biological Systems

Additional Aqueous Equilibria: Chemistry and the Oceans

Thermodynamics: Spontaneous and Nonspontaneous Reactions and Processes

Electrochemistry: The Quest for Clean Energy

Nuclear Chemistry: Applications to Energy and Medicine

Organic and Biological Molecules: the Compounds of Life

The Main Group Elements: Life and the Periodic Table

Transition Metals: Biological and Medical Applications

Filters

What is the hybridization of the carbon atom in CS₂?

What is the bond order of B₂?

What is the bond order of C₂?

Use energy levels of diatomic molecules derived from molecular orbital theory to predict the magnetic properties of F₂ and the dication F₂²^.

What is the valence electron molecular orbital electron configuration of F₂?

Which of the following has a central atom with the same hybridization as the carbon in formaldehyde (CH₂O)?

Consider the molecule below-how many sp² hybridized carbon atoms are present in the compound?

What is the valence electron molecular orbital electron configuration of the O₂^ anion?