Chemistry Atoms First 1st Edition Burdge Overby – Test bank

$20.00

Description

INSTANT DOWNLOAD WITH ANSWERS

Chemistry Atoms First 1st Edition Burdge Overby – Test bank

Chapter 6: Representing Molecules

 

1. The Lewis dot symbol consists of the symbol for the element surrounded by dot(s). What does the symbol represent?
A) Electron configuration D) Atomic mass
B) Valence electrons E) Nucleus and core electrons
C) Atomic number
Ans:  E     Difficulty:  Easy

 

2. The Lewis dot symbol consists of the symbol for the element surrounded by dot(s). What does the dot or dots represent?
A) Electron configuration D) Atomic mass
B) Valence electrons E) Core electrons
C) Atomic number
Ans:  B     Difficulty:  Easy

 

3. Which of the following contains ionic bonding?
A)  CO    B)  SrF2    C)  Al    D)  OCl2    E)  HCl
Ans:  B     Difficulty:  Easy

 

4. How many electrons are in a single bond?
A)  0    B)  1    C)  2    D)  4    E)  6
Ans:  C     Difficulty:  Easy

 

5. How many electrons are in a double bond?
A)  0    B)  1    C)  2    D)  4    E)  6
Ans:  D     Difficulty:  Easy

 

6. How many electrons are in a triple bond?
A)  0    B)  1    C)  2    D)  4    E)  6
Ans:  E     Difficulty:  Easy

 

7. Arrange the following bonds in order of increasing bond strength.
A) C–I < C–Br < C–Cl < C–F D) C–I < C–Br < C–F< C–Cl
B) C–F < C–Cl < C–Br < C–I E) none of these orders is correct
C) C–Br < C–I < C–Cl < C–F
Ans:  A     Difficulty:  Medium

 

8. Select the strongest bond in the following group.
A)  C–S    B)  C–O    C)  C=C    D)  CºN    E)  C–F
Ans:  D     Difficulty:  Easy

 

9. Select the strongest bond in the following group.
A)  C–C    B)  C–O    C)  C=C    D)  CºC    E)  C–F
Ans:  D     Difficulty:  Easy

 

10. Which is the correct order for increasing bond strength? (1) CºC (2) C=C (3) C–C
A) (3) < (2) < (1) D) (1) < (3) < (2)
B) (3) < (1) < (2) E) (2) < (3) < (1)
C) (1) < (2) < (3)
Ans:  A     Difficulty:  Easy

 

11. What types of elements undergo covalent bonding?
A) 1 metal and noble gas D) 2 Group IA elements
B) a nonmetal and a metal E) an actinide
C) 2 nonmetals
Ans:  C     Difficulty:  Easy

 

12. In which of these substances are the atoms held together by polar covalent bonding?
A)  SrCl2    B)  CsCl    C)  ClF    D)  TiF2    E)  S8
Ans:  C     Difficulty:  Easy

 

13. A polar covalent bond would form in which one of these pairs of atoms?
A)  Cl ¾ Cl    B)  Si ¾ Si    C)  Ca ¾ Cl    D)  Cr ¾ Br    E)  P ¾ Cl
Ans:  E     Difficulty:  Easy

 

14. A nonpolar covalent bond (i.e., pure covalent) would form in which of these pairs of atoms?
A)  Na ¾ Cl    B)  H ¾ Cl    C)  Li ¾ Br    D)  Se ¾ Br    E)  Br ¾ Br
Ans:  E     Difficulty:  Easy

 

15. Which of these covalent bonds is the most polar (i.e., highest percent ionic character)?
A)  Al ¾ I    B)  Si ¾ I    C)  Al ¾ Cl    D)  Si ¾ Cl    E)  Si ¾ P
Ans:  C     Difficulty:  Medium

 

16. The covalent bond with the greatest polarity would form in which of these atom pairs?
A)  Br ¾ Br    B)  S ¾ O    C)  C ¾ P    D)  C ¾ O    E)  B ¾ O
Ans:  E     Difficulty:  Medium

 

17. In which of these pairs of atoms would the bond be the least polar (i.e., lowest percent ionic character)?
A)  C ¾ Cl    B)  C ¾ C    C)  C ¾ H    D)  O ¾ C    E)  N ¾ C
Ans:  B     Difficulty:  Medium

 

18. Which of these elements has the greatest electronegativity?
A)  Na    B)  As    C)  Ga    D)  Cs    E)  Sb
Ans:  B     Difficulty:  Medium

 

19. Which of these atoms is the most electronegative?
A)  Li    B)  Cs    C)  P    D)  As    E)  Ge
Ans:  C     Difficulty:  Medium

 

20. Which of these elements is the least electronegative?
A)  Sr    B)  V    C)  Ni    D)  P    E)  I
Ans:  A     Difficulty:  Medium

 

21. Which of the following elements is the most electronegative?
A)  S    B)  Ru    C)  Si    D)  Te    E)  Cs
Ans:  A     Difficulty:  Medium

 

22. Which of the following elements is the least electronegative?
A)  Si    B)  Se    C)  S    D)  Sc    E)  Sr
Ans:  E     Difficulty:  Medium

 

23. Arrange aluminum, nitrogen, phosphorus and indium in order of increasing electronegativity.
A) Al < In < N < P D) In < P < Al < N
B) Al < In < P < N E) None of these orders is correct.
C) In < Al < P < N
Ans:  C     Difficulty:  Medium

 

24. Arrange calcium, rubidium, sulfur, and arsenic in order of decreasing electronegativity.
A) S > As > Rb > Ca D) As > S > Ca > Rb
B) S > As > Ca > Rb E) None of these orders is correct.
C) As > S > Rb > Ca
Ans:  B     Difficulty:  Medium

 

25. Based on electronegativity trends in the periodic table, predict which of the following compounds will have the greatest % ionic character in its bonds.
A)  H2O    B)  LiI    C)  CaO    D)  RbF    E)  HCl
Ans:  D     Difficulty:  Medium

 

26. What is the magnitude of the partial positive and partial negative charges in the HBr molecule? (1D = 3.36 ´ 10–30 C m; 1e = 1.6022 ´ 10–19 C; bond length HBr = 1.41 angstroms; Dipole Moment HBr = 0.82D)
A) –0.36 and +0.36 D) –0.121 and +0.121
B) –0.14 and +0.14 E) –2.73 and +2.73
C) –0.273 and +0.273
Ans:  D     Difficulty:  Medium

 

27. What is the magnitude of the partial positive and partial negative charges in the HI molecule? (1D = 3.36 ´ 10–30 C m; 1e = 1.6022 ´ 10–19 C; bond length HI = 1.61 angstroms; Dipole Moment HI = 0.44 D)
A) –0.76 and +0.76 D) –0.6 and +0.6
B) –0.057 and +0.057 E) –0.911 and +0.911
C) –1.22 and +1.22
Ans:  B     Difficulty:  Medium

 

28. The total number of bonding electrons in a molecule of formaldehyde (H2CO) is
A)  3    B)  4    C)  6    D)  8    E)  18
Ans:  D     Difficulty:  Medium

 

29. The total number of lone pairs in NCl3 is
A)  6    B)  8    C)  9    D)  10    E)  13
Ans:  D     Difficulty:  Medium

 

30. The Lewis structure for CS2 is:
A)      B)      C)      D)
Ans:  C     Difficulty:  Medium

 

31. The Lewis structure for a chlorate ion, ClO3,  should show ____ single bond(s),  ____ double bond(s), and ____ lone pair(s).
A)  2, 1, 10    B)  3, 0, 9    C)  2, 1, 8    D)  3, 0, 10    E)  2, 1, 9
Ans:  D     Difficulty:  Difficult

 

32. Which of these Lewis structures is incorrect?
A)  a    B)  b    C)  c    D)  d    E)  e
Ans:  E     Difficulty:  Difficult

 

33. Which of these choices is a correct Lewis structure for ozone, O3?
A)  a    B)  b    C)  c    D)  d    E)  e
Ans:  D     Difficulty:  Medium

 

34. Which one of the following Lewis structures is definitely incorrect?

 

A)  a    B)  b    C)  c    D)  d    E)  e
Ans:  B     Difficulty:  Difficult

 

35. Hydrazine, N2H4, is a good reducing agent that has been used as a component in rocket fuels. Select its Lewis structure.

 

A)  a    B)  b    C)  c    D)  d    E)  none of these choices is correct
Ans:  C     Difficulty:  Difficult

 

36. Select the correct Lewis structure for nitrogen trifluoride, NF3.

 

A)  a    B)  b    C)  c    D)  d    E)  e
Ans:  A     Difficulty:  Medium

 

37. Select the correct Lewis structure for NOCl, a reactive material used as an ionizing solvent.

 

A)  a    B)  b    C)  c    D)  d    E)  none of these choices is correct
Ans:  B     Difficulty:  Difficult

 

38. The formal charge on the sulfur atom in the resonance structure of sulfur dioxide which has one single bond and one double bond is
A)  0    B)  +1    C)  –1    D)  +2    E)  –2
Ans:  B     Difficulty:  Difficult

 

39. What is the formal charge on phosphorus in a Lewis structure for the phosphate ion that satisfies the octet rule?
A)  –2    B)  –1    C)  0    D)  +1    E)  +2
Ans:  D     Difficulty:  Difficult

 

40. In the best Lewis structure for the fulminate ion, CNO, what is the formal charge on the central nitrogen atom?
A)  +2    B)  +1    C)  0    D)  –1    E)  –2
Ans:  B     Difficulty:  Difficult

 

41. In the Lewis structure of the iodate ion, IO3, that satisfies the octet rule, the formal charge on the central iodine atom is
A)  +2    B)  +1    C)  0    D)  –1    E)  –2
Ans:  A     Difficulty:  Difficult

 

42. Select the Lewis structure for XeO2F2 which correctly minimizes formal charges.

 

 

A)  a    B)  b    C)  c    D)  d    E)  e
Ans:  B     Difficulty:  Difficult

 

43. In the following Lewis structure for ClO3F, chlorine has a formal charge of ____ and an oxidation number of ____.

 

 

A)  7, 7    B)  7, –1    C)  1, 1    D)  1, –1    E)  1, 7
Ans:  E     Difficulty:  Difficult

 

44. In which one of the following structures does the central atom have a formal charge of +2?

 

 

A)  a    B)  b    C)  c    D)  d    E)  e
Ans:  B     Difficulty:  Difficult

 

45. The formal charge on Cl in the structure shown for the perchlorate ion is

 

 

A)  –2    B)  –1    C)  0    D)  +1    E)  +2
Ans:  D     Difficulty:  Difficult

 

46. The number of resonance structures for the sulfur dioxide molecule that satisfy the octet rule is
A)  1    B)  2    C)  3    D)  4    E)  None of these
Ans:  B     Difficulty:  Difficult

 

47. The number of resonance structures for the nitrate ion that satisfy the octet rule is
A)  1    B)  2    C)  3    D)  4    E)  None of these
Ans:  C     Difficulty:  Difficult

 

48. In which one of the following is the best Lewis structure a resonance structure?
A)  SO3    B)  BF3    C)  I3    D)  SCO (C = central atom)    E)  SO32–
Ans:  A     Difficulty:  Difficult

 

49. In which one of the following species is the central atom (the first atom in the formula) likely to violate the octet rule?
A)  BF4    B)  XeO3    C)  SiCl4    D)  NH3    E)  CH2Cl2
Ans:  B     Difficulty:  Difficult

 

50. Which of the following atoms can expand its valence shell when bonding?
A)  N    B)  C    C)  O    D)  P    E)  Al
Ans:  D     Difficulty:  Medium

 

51. Which of these substances will display an incomplete octet in its Lewis structure?
A)  CO2    B)  Cl2    C)  ICl    D)  NO    E)  SO2
Ans:  D     Difficulty:  Medium

 

52. Which of these elements is most likely to exhibit an expanded octet in its compounds?
A)  O    B)  S    C)  Na    D)  C    E)  N
Ans:  B     Difficulty:  Medium

 

53. Which response includes all the molecules below that do not follow the octet rule?  (1) H2S   (2) BCl3   (3) PH3   (4) SF4
A)  (2) and (4)    B)  (2) and (3)    C)  (1) and (2)    D)  (3) and (4)    E)  (1) and (4)
Ans:  A     Difficulty:  Difficult

 

54. Which of these molecules has an atom with an expanded octet?
A)  HCl    B)  AsCl5    C)  ICl    D)  NCl3    E)  Cl2
Ans:  B     Difficulty:  Medium

 

55. Which molecule has a Lewis structure that does not obey the octet rule?
A)  N2O    B)  CS2    C)  PH3    D)  CCl4    E)  NO2
Ans:  E     Difficulty:  Medium

 

56. Ionic compounds tend to form between metals and nonmetals when electrons are transferred from an element with high ionization energy (metal) to an element with a low electron affinity (nonmetal).
Ans:  False     Difficulty:  Medium

 

57. Lewis theorized the octet rule to describe chemical bonding where atoms lose, gain, or share electrons in order to achieve a noble gas configuration.
Ans:  True     Difficulty:  Easy

 

58. Only valence electrons are shown in the Lewis structure held together by covalent bonds.
Ans:  True     Difficulty:  Easy

 

59. A double bond can not exist between a carbon atom and an oxygen atom.
Ans:  False     Difficulty:  Easy

 

60. A triple bond can not exist between a carbon atom and a hydrogen atom.
Ans:  True     Difficulty:  Easy

 

61. Unshared electrons are always shown in pairs around an atom.
Ans:  False     Difficulty:  Easy

 

62. The octet rule works best for elements in the 3rd period of the periodic table.
Ans:  False     Difficulty:  Medium

 

63. Multiple bonds are longer than single bonds.
Ans:  False     Difficulty:  Easy

 

64. Single bonds are stronger than multiple bonds.
Ans:  False     Difficulty:  Easy

 

65. What theory describes atoms losing, gaining, or sharing electrons to achieve a noble gas configuration?
Ans: octet rule
Difficulty:  Easy

 

66. What is the distance between the nuclei of two covalently bonded atoms in a molecule?
Ans: bond length
Difficulty:  Easy

 

67. What term describes the ability of an atom in a compound to pull the electrons to itself?
Ans: electronegativity
Difficulty:  Easy

 

68. How many lone pairs of electrons are on the central atom in the Lewis structure for NH3?
Ans: 1
Difficulty:  Easy

 

69. Give the equation for percent ionic character.
Ans: (observed dipole moment/calculated dipole moment assuming discrete charges) ´ 100%
Difficulty:  Medium

 

70. Give the equation for formal charge.
Ans: # valence electrons – (1/2)(bonded electrons) – lone electrons
Difficulty:  Medium

 

71. The number of dots in the Lewis dot symbol for a main group element is the same as the ___________   ___________.
Ans: group number
Difficulty:  Easy

 

72. ___________   ___________ of atoms interact to form compounds.
Ans: Valence electrons
Difficulty:  Easy

 

73. In the Lewis dot symbol, the element symbol represents the ________   _________ and the dots represent the __________ ___________.
Ans: core electrons; valence electrons
Difficulty:  Easy

 

74. A triple bond arises when two atoms share ___________ pairs of electrons.
Ans: three
Difficulty:  Easy

 

75. A single bond between two atoms represents ________ pair(s) of electrons
Ans: one
Difficulty:  Easy

 

76. ______________ is a representation of covalent bonding in which shared electron pairs are shown either as dashes or as pairs of dots between two atoms and unshared electrons are shown as dots around the individual atoms.
Ans: Lewis structure
Difficulty:  Easy

 

77. Using appropriate, real examples to illustrate your answer, describe the correlation between bond energy and bond length for a series of single bonds.
Ans: The bonds between carbon, C, and the halogens, X (X = F, Cl, Br, I) can be used as an examples. The size of X increases as one moves down the group. This means that the C–X bond length will become correspondingly longer. As this occurs the bond becomes weaker. Thus, the C–I bond is the longest and weakest, C–F the shortest and strongest of the series.
Difficulty:  Medium

 

78. Using appropriate, real examples to illustrate your answer, describe the correlation between bond energy and bond length for a series of varying bond order.
Ans: Carbon and oxygen form single, double and triple bonds. The CºO bond in carbon monoxide is roughly three times as strong as the C–O single bond, while the C=O bond is about twice as strong as the single bond. The bond energy is approximately proportional to the bond order.
Difficulty:  Medium

 

79. Describe in brief how electronegativity values can be used to predict the percent ionic character of a bond between two atoms.
Ans: Take the electronegativity difference (DEN) of the bonded atoms. The larger the difference between their electronegativities, the more ionic will be the nature of the bond. If DEN = 0, the bond will be pure covalent.
Difficulty:  Medium

 

Chapter 7: Molecular Geometry and Bonding Theories

 

1. What does VSEPR model mean?
A) Very Specific Electron and Proton Repair model
B) Variable Selective of Electron and PRotons
C) Valence Shell for Every Proton
D) Very Selective Electron PaiR theory
E) Valence Shell Electron-Pair Repulsion
Ans:  E     Difficulty:  Easy

 

2. Which of the following is required for determination of the VSEPR model and the molecular shape?
A) Atomic mass D) Lewis structure
B) # of protons E) None of the answers is correct
C) Oxidation number
Ans:  D     Difficulty:  Easy

 

3. According to the VSEPR theory, the shape of the SO3 molecule is
A) pyramidal. D) distorted tetrahedron (seesaw).
B) tetrahedral. E) square planar.
C) trigonal planar.
Ans:  C     Difficulty:  Medium

 

4. What is the molecular shape of the CH4 molecule?
A) tetrahedral. D) square planar.
B) trigonal pyramidal E) distorted tetrahedron (seesaw).
C) trigonal planar.
Ans:  A     Difficulty:  Easy

 

5. Use VSEPR theory to predict the shape of the PCl3 molecule.
A)  linear    B)  bent    C)  trigonal planar    D)  trigonal pyramidal    E)  tetrahedral
Ans:  D     Difficulty:  Medium

 

6. What is the molecular shape of the H2O molecule?
A) tetrahedral. D) square planar.
B) trigonal pyramidal E) distorted tetrahedron (seesaw).
C) bent.
Ans:  C     Difficulty:  Easy

 

7. What is the molecular shape of the IBr3 molecule?
A) tetrahedral. D) trigonal planar.
B) T-shaped E) distorted tetrahedron (seesaw).
C) bent.
Ans:  B     Difficulty:  Medium

 

8. According to the VSEPR theory, the molecular shape of the carbonate ion, CO32 –, is
A) square planar. D) trigonal planar.
B) tetrahedral. E) octahedral.
C) pyramidal.
Ans:  D     Difficulty:  Medium

 

9. According to the VSEPR theory, the molecular shape of SiCl4 is
A)  linear.    B)  trigonal planar.    C)  bent.    D)  tetrahedral.    E)  trigonal pyramidal.
Ans:  D     Difficulty:  Easy

 

10. According to the VSEPR theory, the molecular shape of ammonia is
A)  linear.    B)  trigonal planar.    C)  bent.    D)  tetrahedral.    E)  trigonal pyramidal.
Ans:  E     Difficulty:  Medium

 

11. According to the VSEPR theory, which one of the following species should be linear?
A)  H2S    B)  HCN    C)  BF3    D)  H2CO    E)  SO3
Ans:  B     Difficulty:  Medium

 

12. According to VSEPR theory, which one of the following molecules should have a shape that is trigonal bipyramidal?
A)  SF4    B)  XeF4    C)  NF3    D)  SF6    E)  PF5
Ans:  E     Difficulty:  Medium

 

13. Which one of the following molecules has tetrahedral geometry?
A)  XeF4    B)  BF3    C)  AsF5    D)  CF4    E)  NH3
Ans:  D     Difficulty:  Medium

 

14. Predict the geometry around the central atom in PO43–.
A) trigonal planar. D) trigonal bipyramidal.
B) trigonal pyramidal. E) octahedral.
C) tetrahedral.
Ans:  C     Difficulty:  Medium

 

15. Predict the geometry around the central atom in SO32–.
A) trigonal planar. D) trigonal bipyramidal.
B) trigonal pyramidal. E) octahedral.
C) tetrahedral.
Ans:  B     Difficulty:  Medium

 

16. What is the total number of electron domains for a molecule having a trigonal pyramidal molecular geometry such as NH3?
A)  5    B)  2    C)  3    D)  4    E)  6
Ans:  D     Difficulty:  Medium

 

17. What is the total number of electron domains for a molecule having a T-shaped pyramidal molecular geometry such as BrF3?
A)  5    B)  2    C)  3    D)  4    E)  6
Ans:  A     Difficulty:  Medium

 

18. What is the total number of electron domains for a molecule having a square pyramidal molecular geometry such as ClF5?
A)  5    B)  2    C)  3    D)  4    E)  6
Ans:  E     Difficulty:  Medium

 

19. What is the total number of electron domains for a molecule having a square planar molecular geometry such as XeBr4?
A)  5    B)  2    C)  3    D)  4    E)  6
Ans:  E     Difficulty:  Medium

 

20. What is the number of lone electron pairs on the central atom of a molecule having a molecular geometry of seesaw-shaped such as SF4?
A)  1    B)  2    C)  3    D)  4    E)  6
Ans:  A     Difficulty:  Medium

 

21. What is the number of lone electron pairs on the central atom of a molecule having a trigonal pyramidal molecular geometry such as NH3?
A)  1    B)  2    C)  3    D)  0    E)  4
Ans:  A     Difficulty:  Medium

 

22. What is the number of lone electron pairs on the central atom of a molecule having a linear molecular geometry such as CO2?
A)  1    B)  2    C)  3    D)  0    E)  4
Ans:  D     Difficulty:  Medium

 

23. What is the number of lone electron pairs on the central atom of a molecule having a linear molecular geometry such as ClF2?
A)  1    B)  2    C)  3    D)  0    E)  4
Ans:  C     Difficulty:  Medium

 

24. According to VSEPR theory, a molecule with the general formula AX3Eo will have a ______ molecular shape.
A)  linear.    B)  bent.    C)  trigonal planar.    D)  tetrahedral.    E)  trigonal pyramidal.
Ans:  C     Difficulty:  Medium

 

25. According to VSEPR theory, a molecule with the general formula AX5Eo will have a ______ molecular shape.
A) tetrahedral. D) trigonal bipyramidal.
B) trigonal planar. E) see-saw.
C) trigonal pyramidal.
Ans:  D     Difficulty:  Medium

 

26. According to VSEPR theory, a molecule with the general formula AX2E2 will have a _____ molecular shape.
A)  linear.    B)  bent.    C)  trigonal planar.    D)  tetrahedral.    E)  see-saw.
Ans:  B     Difficulty:  Medium

 

27. According to VSEPR theory, a molecule with the general formula AX4E2 will have a _____ molecular shape.
A) tetrahedral. D) octahedral.
B) square pyramidal. E) see-saw.
C) square planar.
Ans:  C     Difficulty:  Medium

 

28. According to VSEPR theory, a molecule with the general formula AX5E will have a ______ molecular shape.
A) tetrahedral. D) octahedral.
B) trigonal bipyramidal E) see-saw.
C) square pyramidal
Ans:  C     Difficulty:  Medium

 

29. What is the molecular shape of N2O as predicted by the VSEPR theory?

 

A)  trigonal pyramidal    B)  trigonal planar    C)  angular    D)  bent    E)  linear
Ans:  E     Difficulty:  Medium

 

30. What is the molecular shape of the thiocyanate anion, SCN, as predicted by the VSEPR theory? (Carbon is the central atom.)
A)  linear    B)  bent    C)  angular    D)  trigonal    E)  none of these choices is correct
Ans:  A     Difficulty:  Medium

 

31. What is the molecular shape of BeH2 as predicted by the VSEPR theory?
A)  linear    B)  bent    C)  angular    D)  trigonal    E)  none of these choices is correct
Ans:  A     Difficulty:  Medium

 

32. What is the molecular shape of NOCl as predicted by the VSEPR theory?

 

 

A)  linear    B)  trigonal planar    C)  bent    D)  tetrahedral    E)  trigonal pyramidal
Ans:  C     Difficulty:  Medium

 

33. What is the molecular shape of NO2 as predicted by the VSEPR theory?
A)  linear    B)  trigonal planar    C)  bent    D)  tetrahedral    E)  resonant
Ans:  C     Difficulty:  Medium

 

34. What is the molecular shape of ClO3F as predicted by the VSEPR theory?

 

 

A) trigonal pyramidal D) tetrahedral
B) square planar E) octahedral
C) square pyramidal
Ans:  D     Difficulty:  Medium

 

35. What is the molecular shape of HOF as predicted by the VSEPR theory?
A)  trigonal pyramidal    B)  trigonal    C)  tetrahedral    D)  linear    E)  bent
Ans:  E     Difficulty:  Medium

 

36. What is the molecular shape of XeO2F2 as predicted by the VSEPR theory?

 

 

A) square planar D) see-saw
B) tetrahedral E) octahedral
C) square pyramidal
Ans:  D     Difficulty:  Medium

 

37. What is the molecular shape of ClF2 as predicted by the VSEPR theory?
A)  linear    B)  bent    C)  see-saw    D)  T-shaped    E)  L-shaped
Ans:  A     Difficulty:  Medium

 

38. What is the molecular shape of SiF62– as predicted by the VSEPR theory?

 

 

A) trigonal bipyramidal D) see-saw
B) hexagonal E) octahedral
C) tetrahedral
Ans:  E     Difficulty:  Medium

 

39. Use VSEPR theory to predict the electron group arrangement around iodine, the central atom in the ion IF2.
A) octahedral D) trigonal planar
B) trigonal bipyramidal E) bent
C) tetrahedral
Ans:  B     Difficulty:  Medium

 

40. Use VSEPR theory to decide which one of the following molecules and ions will definitely have at least one 90° bond angle in it. (In each case except water, the central atom is the first one in the formula.)
A)  AlCl4    B)  NH3    C)  PCl5    D)  CO2    E)  H2O
Ans:  C     Difficulty:  Medium

 

41. What is the approximate bond angle for CCl4?
A)  90°    B)  109.5°    C)  120°    D)  145°    E)  180°
Ans:  B     Difficulty:  Easy

 

42. The F – S – F bond angles in SF6 are
A)  90° and 180°    B)  109.5°    C)  120°    D)  180°    E)  90° and 120°
Ans:  A     Difficulty:  Medium

 

43. What is the approximate bond angle for NH3?
A)  90°    B)  109.5°    C)  120°    D)  107°    E)  105°
Ans:  D     Difficulty:  Medium

 

44. What is the approximate bond angle for CO2?
A)  90°    B)  109.5°    C)  120°    D)  107°    E)  180°
Ans:  E     Difficulty:  Medium

 

45. What is the approximate bond angle for H2O?
A)  90°    B)  109.5°    C)  120°    D)  107°    E)  105°
Ans:  E     Difficulty:  Medium

 

46. Predict the ideal bond angles in AsCl3 using the molecular shape given by the VSEPR theory.
A)  90°    B)  109°    C)  120°    D)  180°    E)  between 110 and 120°
Ans:  B     Difficulty:  Medium

 

47. Predict the actual bond angles in BrF3 using the VSEPR theory.
A) more than 120° D) between 90° and 109°
B) exactly 120° E) less than 90°
C) between 109° and 120°
Ans:  E     Difficulty:  Medium

 

48. What is the approximate bond angle for CH4?
A)  90°    B)  109.5°    C)  120°    D)  107°    E)  105°
Ans:  B     Difficulty:  Easy

 

49. How do you describe the molecular geometry of a molecule that does not have a central atom?
A) Describe the molecular geometry around the most electronegative atom.
B) Describe the molecular geometry around all non-hydrogen atoms.
C) Describe the molecular geometry around the most electropositive atom.
D) Describe the molecular geometry around the atom with the largest atomic radius.
E) Describe the molecular geometry around the atom with the largest bond angle.
Ans:  B     Difficulty:  Medium

 

50. Which one of the following molecules is nonpolar?
A)  NH3    B)  OF2    C)  CH3Cl    D)  H2O    E)  BeCl2
Ans:  E     Difficulty:  Difficult

 

51. Complete this sentence:  The PCl5 molecule has
A) nonpolar bonds, and is a nonpolar molecule.
B) nonpolar bonds, but is a polar molecule.
C) polar bonds, and is a polar molecule.
D) polar bonds, but is a nonpolar molecule.
Ans:  D     Difficulty:  Difficult

 

52. Which one of the following molecules is nonpolar?
A)  CO2    B)  BF3    C)  KCl    D)  IBr3    E)  CHCl3
Ans:  A     Difficulty:  Difficult

 

53. Which one of the following molecules has a zero dipole moment?
A)  CO    B)  CH2Cl2    C)  SO3    D)  SO2    E)  NH3
Ans:  C     Difficulty:  Difficult

 

54. What is the dipole moment for CO2?
A) –1 D) need more information
B) 0 E) None of the answers is correct
C) +1
Ans:  B     Difficulty:  Medium

 

55. Which one of the following molecules is polar?
A)  PBr5    B)  CCl4    C)  BrF5    D)  XeF2    E)  XeF4
Ans:  C     Difficulty:  Difficult

 

56. Predict the molecular geometry and polarity of the SO2 molecule.
A) linear, polar D) bent, nonpolar
B) linear, nonpolar E) None of the above.
C) bent, polar
Ans:  C     Difficulty:  Difficult

 

57. Predict the geometry and polarity of the CS2 molecule.
A) linear, polar D) bent, nonpolar
B) linear, nonpolar E) bent, polar
C) tetrahedral, nonpolar
Ans:  B     Difficulty:  Difficult

 

58. Which one of the following molecules is polar?
A)  CH4    B)  CHBr3    C)  F2    D)  CBr4    E)  CO2
Ans:  B     Difficulty:  Difficult

 

59. Which of the following molecules has a net dipole moment?
A)  BeCl2    B)  SF2    C)  KrF2    D)  CO2    E)  CCl4
Ans:  B     Difficulty:  Difficult

 

60. Which of the following has no net dipole moment?
A)  N2O    B)  NF3    C)  H2Se    D)  TeO3    E)  CH3Cl
Ans:  D     Difficulty:  Difficult

 

61. Which of the following atoms, in the ground state, has unpaired electrons?
A)  Ca    B)  Ne    C)  Mg    D)  He    E)  C
Ans:  E     Difficulty:  Easy

 

62. Which of the following atoms, in the ground state, does not have unpaired electrons?
A)  P    B)  Na    C)  Ne    D)  C    E)  S
Ans:  C     Difficulty:  Easy

 

63. How many bonds should an oxygen atom form?
A)  1    B)  2    C)  3    D)  6    E)  4
Ans:  B     Difficulty:  Easy

 

64. How many bonds should a carbon atom form?
A)  1    B)  2    C)  3    D)  6    E)  4
Ans:  E     Difficulty:  Easy

 

65. How many bonds should a fluorine atom form?
A)  1    B)  2    C)  3    D)  6    E)  4
Ans:  A     Difficulty:  Easy

 

66. Indicate the type of hybrid orbitals used by the central atom in PCl3.
A)  sp    B)  sp2    C)  sp3    D)  sp3d    E)  sp3d2
Ans:  C     Difficulty:  Difficult

 

67. Indicate the type of hybrid orbitals used by the central atom in CCl4.
A)  sp    B)  sp2    C)  sp3    D)  sp3d    E)  sp3d2
Ans:  D     Difficulty:  Medium

 

68. Indicate the type of hybrid orbitals used by the central atom in SF6.
A)  sp    B)  sp2    C)  sp3    D)  sp3d    E)  sp3d2
Ans:  E     Difficulty:  Medium

 

69. What is the hybridization of the As atom in the AsF5 molecule?
A)  sp    B)  sp2    C)  sp3    D)  sp3d    E)  sp3d2
Ans:  D     Difficulty:  Medium

 

70. What is the hybridization on the central atom in NO3?
A)  sp    B)  sp2    C)  sp3    D)  sp3d    E)  sp3d2
Ans:  B     Difficulty:  Difficult

 

71. In which one of the following molecules is the central atom sp2 hybridized?
A)  SO2    B)  N2O    C)  BeCl2    D)  NF3    E)  PF5
Ans:  A     Difficulty:  Difficult

 

72. What is the hybridization of As in the AsF4 ion?
A)  sp    B)  sp2    C)  sp3    D)  sp3d    E)  sp3d2
Ans:  D     Difficulty:  Difficult

 

73. What is the hybridization of the central atom in ClO3?
A)  sp    B)  sp2    C)  sp3    D)  sp3d    E)  sp3d2
Ans:  C     Difficulty:  Difficult

 

74. The hybridization of the central nitrogen atom in the molecule N2O is
A)  sp    B)  sp2    C)  sp3    D)  sp3d    E)  sp3d2
Ans:  A     Difficulty:  Difficult

 

75. A molecule with the formula AX2 uses _________ to form its bonds.
A) sp hybrid orbitals D) sp3d hybrid orbitals
B) sp2 hybrid orbitals E) sp3d2 hybrid orbitals
C) sp3 hybrid orbitals
Ans:  A     Difficulty:  Difficult

 

76. A molecule with the formula AX4 uses _________ to form its bonds.
A) sp hybrid orbitals D) sp3d hybrid orbitals
B) sp2 hybrid orbitals E) sp3d2 hybrid orbitals
C) sp3 hybrid orbitals
Ans:  C     Difficulty:  Difficult

 

77. A molecule with the formula AX4E2 uses _________ to form its bonds.
A) sp hybrid orbitals D) sp3d hybrid orbitals
B) sp2 hybrid orbitals E) sp3d2 hybrid orbitals
C) sp3 hybrid orbitals
Ans:  E     Difficulty:  Difficult

 

78. Carbon uses ______ hybrid orbitals in ClCN.
A)  sp    B)  sp2    C)  sp3    D)  sp3d    E)  sp3d2
Ans:  A     Difficulty:  Difficult

 

79. Valence bond theory predicts that carbon will use _____ hybrid orbitals in the carbonate anion, CO32–.
A)  sp    B)  sp2    C)  sp3    D)  sp3d    E)  sp3d2
Ans:  B     Difficulty:  Difficult

 

80. Valence bond theory predicts that sulfur will use _____ hybrid orbitals in sulfur dioxide, SO2.
A)  sp    B)  sp2    C)  sp3    D)  sp3d    E)  sp3d2
Ans:  B     Difficulty:  Difficult

 

81. When PCl5 solidifies it forms PCl4+ cations and PCl6anions. According to valence bond theory, what hybrid orbitals are used by phosphorus in the PCl4+ cations?
A)  sp    B)  sp2    C)  sp3    D)  sp3d    E)  sp3d2
Ans:  C     Difficulty:  Difficult

 

82. Valence bond theory predicts that iodine will use _____ hybrid orbitals in ICl2.
A)  sp2    B)  sp3    C)  sp3d    D)  sp3d2    E)  none of these choices is correct
Ans:  C     Difficulty:  Difficult

 

83. Which one of the following statements about orbital hybridization is incorrect?
A) The carbon atom in CH4 is sp3 hybridized.
B) The carbon atom in CO2 is sp hybridized.
C) The nitrogen atom in NH3 is sp2 hybridized.
D) sp2 hybrid orbitals are coplanar, and at 120° to each other.
E) sp hybrid orbitals lie at 180° to each other.
Ans:  C     Difficulty:  Difficult

 

84. For which one of the following molecules is the indicated type of hybridization not appropriate for the central atom?
A) BeCl2     sp2 D) C2H2     sp
B) SiH4          sp3 E) H2O          sp3
C) BF3          sp2
Ans:  A     Difficulty:  Difficult

 

85. Determine the shape (geometry) of PCl3 and then decide on the appropriate hybridization of phosphorus in this molecule. (Phosphorus is the central atom.)
A)  sp3    B)  sp2    C)  sp    D)  sp3d    E)  sp3d2
Ans:  A     Difficulty:  Difficult

 

86. The number of pi bonds in the molecule below is
A)  1    B)  2    C)  3    D)  5    E)  9
Ans:  C     Difficulty:  Medium

 

87. The number of pi bonds in the molecule below is
A)  2    B)  4    C)  6    D)  10    E)  15
Ans:  B     Difficulty:  Medium

 

88. According to valence bond theory, the triple bond in ethyne (acetylene, C2H2) consists of
A) three s bonds and no p bonds. D) no s bonds and three p bonds.
B) two s bonds and one p bond. E) none of these choices is correct
C) one s bond and two p bonds.
Ans:  C     Difficulty:  Medium

 

89. The number of pi bonds in the oxalate ion (C2O42–) is
A)  1    B)  2    C)  3    D)  4    E)  5
Ans:  B     Difficulty:  Difficult

 

90. Consider the species Cl2+, Cl2, and Cl2.  Which of these species will be paramagnetic?
A) Only Cl2 D) Cl2+ and Cl2
B) Cl2+ and Cl2 E) All three are paramagnetic
C) Cl2 and Cl2
Ans:  D     Difficulty:  Medium

 

91. Consider the species N2, N2, and N2+.  Which of these species will be paramagnetic?
A) N2 and N2 D) Only N2
B) N2+ and N2 E) None are paramagnetic
C) N2+ and N2
Ans:  C     Difficulty:  Medium

 

92. Which of the following is not true of molecular orbitals?
A) The number of molecular orbitals formed is always equal to the number of atomic orbitals combined.
B) A molecular orbital can accommodate up to two electrons.
C) When electrons are added to orbitals of the same energy, the most stable arrangement is predicted by Hund’s rule.
D) Low-energy molecular orbitals fill before high-energy molecular orbitals fill.
E) For any substance, the number of electrons in molecular orbitals is equal to the sum of all the valence electrons on the bonding atoms.
Ans:  E     Difficulty:  Medium

 

93. The electrons in the delocalized molecular orbitals of benzene (C6H6)
A) are confined between two adjacent bonding atoms.
B) are free to move around the six-membered ring.
C) form the electron pairs in the C–H bonds of the compound.
D) are unevenly distributed through the molecule.
E) are responsible for the fact that the bonds between three pairs of carbon atoms in the ring are longer and stronger than the bonds between the other three pairs of carbon atoms.
Ans:  B     Difficulty:  Medium

 

94. According to molecular orbital (MO) theory, the twelve outermost electrons in the O2 molecule are distributed as follows:
A) 12 in bonding MOs, 0 in antibonding MOs.
B) 10 in bonding MOs, 2 in antibonding MOs.
C) 9 in bonding MOs, 3 in antibonding MOs.
D) 8 in bonding MOs, 4 in antibonding MOs.
E) 7 in bonding MOs, 5 in antibonding MOs.
Ans:  D     Difficulty:  Medium

 

95. According to molecular orbital theory, what is the bond order in the O2+ ion?
A)  5.5    B)  5    C)  4    D)  2.5    E)  1.5
Ans:  D     Difficulty:  Medium

 

96. The nitrosonium ion, NO+, forms a number of interesting complexes with nickel, cobalt, and iron. According to molecular orbital theory, which of the following statements about NO+ is correct?
A) NO+ has a bond order of 2 and is paramagnetic.
B) NO+ has a bond order of 2 and is diamagnetic.
C) NO+ has a bond order of 3 and is paramagnetic.
D) NO+ has a bond order of 3 and is diamagnetic.
E) None of these statements is correct.
Ans:  D     Difficulty:  Difficult

 

97. The BrF5 molecule has polar bonds and has a net dipole moment.
Ans:  True     Difficulty:  Medium

 

98. Pi bonds are covalent bonds in which the electron density is concentrated above and below the plane of the nuclei of the bonding atoms.
Ans:  True     Difficulty:  Easy

 

99. The number of lone pairs of electrons on the central atoms is the main factor that is used to determine the molecular shape or molecular geometry.
Ans:  True     Difficulty:  Easy

 

100. According to VSEPR theory, a molecule with the general formula AX3E2 (where E represents a lone pair on A) will be trigonal planar.
Ans:  False     Difficulty:  Medium

 

101. A molecule which contains polar bonds will always have a dipole moment.
Ans:  False     Difficulty:  Medium

 

102. To make a sp3 hybrid orbital, one s orbital is mixed with 3 p orbitals.
Ans:  True     Difficulty:  Easy

 

103. The bond angle for a sp hybrid orbital is smaller than the bond angle for a sp2 hybrid orbital.
Ans:  False     Difficulty:  Medium

 

104. The angles between sp2 hybrid orbitals are 109.5°.
Ans:  False     Difficulty:  Medium

 

105. Atoms of period 3 and beyond can undergo sp3d 2 hybridization, but atoms of period 2 cannot.
Ans:  True     Difficulty:  Medium

 

106. In the valence bond treatment, overlap of an s orbital on one atom with an sp3 orbital on another atom can give rise to a s bond.
Ans:  True     Difficulty:  Medium

 

107. In the valence bond treatment, a p bond is formed when two 2p orbitals overlap side to side
Ans:  True     Difficulty:  Easy

 

108. According to molecular orbital theory, all diatomic molecules with an even number of electrons will be diamagnetic.
Ans:  False     Difficulty:  Medium

 

109. To correctly determine the molecular shape of a molecule requires that you first draw the Lewis structure for the molecule.
Ans:  True     Difficulty:  Easy

 

110. Use VSEPR theory to predict the molecular geometry of H3O+ (hydronium ion).
Ans: trigonal pyramidal
Difficulty:  Medium

 

111. Use VSEPR theory to predict the molecular geometry of CO32–
Ans: trigonal planar
Difficulty:  Medium

 

112. The N – N – H bond angles in hydrazine N2H4 are 112°.  What is the hybridization of the nitrogen orbitals predicted by valence bond theory?
Ans: sp3.
Difficulty:  Medium

 

113. How many p-bonds in CH3COCH3?
Ans: one.
Difficulty:  Medium

 

114. According to the VSEPR theory, will the molecule PF5 be polar or nonpolar?
Ans: nonpolar
Difficulty:  Medium

 

115. How many electron domains are on the central atom for a sp2 hybridized atom?
Ans: 3
Difficulty:  Medium

 

116. How many electron domains are on the central atom for a sp3d hybridized atom?
Ans: 5
Difficulty:  Medium

 

117. What name is given to the shape of a molecule with no lone pairs of electrons on the central atom and 6 electron domains on the central atom?
Ans: Octahedral
Difficulty:  Easy

 

118. The total number of electron domains is used to determine the ___________.
Ans: Electron-Domain Geometry
Difficulty:  Easy

 

119. The number of lone pairs on the central atoms is used to determine the ____________.
Ans: Molecular Geometry
Difficulty:  Easy

 

120. Complete the following table.

Hybrid type Geometry of electron pairs
a     __________ linear
b     sp3 __________
c     __________ trigonal bipyramidal
d     __________ octahedral
e     sp __________
Ans:
Hybrid type Geometry of electron pairs
a     sp linear
b     sp3 tetrahedral
c     sp3d trigonal bipyramidal
d     sp3d2 octahedral
e     sp trigonal planar
Difficulty:  Medium

 

121. ___________ _________ results from parallel overlap of two p orbitals.
Ans: p-bonds
Difficulty:  Easy

 

122. Water has ___________ number of lone pairs of electrons on the central oxygen.
Ans: two
Difficulty:  Easy

 

123. ___________ is the electron-domain geometry and _________ is the molecular shape for ammonia.
Ans: tetrahedral and pyramidal
Difficulty:  Medium

 

124. The bond angle for the carbonate ion is ___________.
Ans: 1200
Difficulty:  Medium

 

125. Draw a Lewis structure for PF5 that shows the correct atom arrangement predicted by the VSEPR theory.
Ans:
Difficulty:  Medium

 

126. The Lewis structure of formaldehyde, CH2O, is shown. Use VSEPR theory to predict the molecular geometry and the H–C–H bond angle. Outline your reasoning.

 

Ans: There are three electron groups around the central atom, carbon. These are a double bond and two single bonds. The molecule is thus of the AX3 type, and its geometry will be trigonal planar. The bond angles will be 120°.
Difficulty:  Medium

 

127. Draw the Lewis structure of XeF4. Use this structure, in conjunction with VSEPR theory, to predict the shape of this molecule. Outline your reasoning.
Ans: The Lewis structure is shown alongside. The VSEPR formula is AX4E2, and the electron group arrangement is therefore octahedral. The lone pairs will lie at opposite vertices, resulting in a square planar molecular geometry.
Difficulty:  Difficult

 

128. In one sentence state the basic principle of valence bond theory.
Ans: A covalent bond forms when the orbitals of two atoms overlap and a pair of electrons occupies the region between the nuclei.
Difficulty:  Easy

 

129. In not more than two sentences, explain when and why chemists make use of the concept of hybridization.
Ans: Chemists postulate hybridization when the observed geometry of a molecule cannot be rationalized in terms of overlap of the s, p and/or d orbitals of the atoms concerned.
Difficulty:  Medium

 

130. In one sentence state how molecular orbitals are usually obtained.
Ans: By the linear combination (addition or subtraction) of atomic orbitals.
Difficulty:  Medium