Chapter 10 Test Bank

Chapter 10 - Molecular Geometry and Chemical Bonding Theory

1. Which molecule or ion does not have a trigonal pyramidal molecular geometry?

A) PO33–

B) SO32–

C) NI3 D) BF3 E) XeO3

ANS: D PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | tetrahedral arrangement MSC: general chemistry

2. What is the electron geometry (or electron arrangement) around an atom in a molecule or

ion which is surrounded by zero lone pairs of electrons and four single bonds. A) tetrahedral B) trigonal pyramidal C) trigonal planar D) bent E) linear

ANS: A PTS: 1 DIF: easy REF: 10.1 OBJ: Electron Geometry-4 electron pairs TOP: bonding | molecular geometry

3. What is the molecular geometry around an atom in a molecule or ion which is surrounded

by zero lone pairs of electrons and four single bonds. A) tetrahedral B) linear C) bent D) trigonal pyramidal E) trigonal planar

ANS: A PTS: 1 DIF: easy REF: 10.1 OBJ: Molecular Geometry-4 electron pairs TOP: bonding | molecular geometry


by one lone pair of electrons and four single bonds. A) see-saw or distorted tetrahedron B) trigonal bipyramidal C) linear D) T-shaped E) trigonal planar



ion which is surrounded by one lone pair of electrons and four single bonds. A) trigonal bipyramidal B) see-saw or distorted tetrahedron C) T-shaped D) linear E) trigonal planar



ion which is surrounded by one lone pair of electrons and five single bonds. A) octahedral B) square pyramidal C) square planar D) bent E) linear



by four single bonds and no lone pairs of electrons. A) tetrahedral B) trigonal bipyramidal C) octahedral D) linear E) trigonal planar

ANS: A PTS: 1 DIF: easy REF: 10.1 OBJ: Molecular Geometry-2-6 bonding pair TOP: bonding | molecular geometry


by zero lone pairs of electrons and six single bonds. A) octahedral B) square planar C) square pyramidal D) bent E) linear


9. Which molecule or ion has a trigonal planar molecular geometry?

A) PCl3

B) HCN C) CO3

2– D) HCCH E) AsF3

ANS: C PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | trigonal planar arrangement MSC: general chemistry

10. Which molecule or ion has a trigonal pyramidal molecular geometry?

A) H2CO B) H2CCO C) CH3

+ D) CH3

– E) C2H4

ANS: D PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | trigonal planar arrangement MSC: general chemistry

11. Which molecule or ion is not planar?

A) H2CO B) NO2

– C) C2F4 D) H2CCO E) PO4

3–

ANS: E PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model MSC: general chemistry


A) XeF4 B) NO3

– C) BCl3 D) F2CCF2 E) CF4


13. Which molecule or ion has a trigonal pyramidal molecular geometry?

A) BF3 B) C2H4

C) SO3 D) SO3

2– E) CO3

2–


14. Which molecule or ion has the same molecular geometry for its central atom as the

carbonate ion? A) H2CO B) AsCl3 C) PF3 D) CH3

– E) BrO3

–

ANS: A PTS: 1 DIF: moderate REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | trigonal planar arrangement MSC: general chemistry

15. Which molecule or ion is nonlinear?

A) CO2 B) NF2

– C) OCN– D) NO2

+ E) HCCH

ANS: B PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model MSC: general chemistry


A) N2O B) O3 C) OCN– D) NO2

+ E) CS2



A) NO2+

B) SO2

C) NNO D) CS2 E) SCN–


18. The approximate CCO angle in acetone, , is A) 180°. B) 90°. C) 109°. D) 60°. E) 120°.

ANS: E PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: bond angle MSC: general chemistry

19. The approximate H—C—H bond angle in CH3

+ is A) 60°. B) 90°. C) 120°. D) 109°. E) 180°.

ANS: C PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: bond angle MSC: general chemistry

20. The approximate H—C—C bond angle in ethane, C2H6, is

A) 60°. B) 180°. C) 120°. D) 109°. E) 90°.

ANS: D PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: bond angle MSC: general chemistry

21. The molecule AX3, in which A is the central atom, is polar and obeys the octet rule;

therefore, A) A has two lone pairs. B) A has one lone pair. C) A has no lone pairs. D) A has four bonding pairs. E) A has three lone pairs.

ANS: B PTS: 1 DIF: moderate REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | tetrahedral arrangement MSC: general chemistry

22. What is the predicted H—N—H bond angle in the ammonium ion?

A) 109.5° B) 90° C) 180° D) 120° E) 45°

ANS: A PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: bond angle MSC: general chemistry

23. What is the O—N—O bond angle in the nitrite ion?

A) 90° B) 180° and 90° C) 180° D) 120° E) 109°

ANS: D PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: bond angle MSC: general chemistry

24. What is the bond angle in a linear molecule or ion?

A) 120° B) 109° C) 90° D) 72° E) 180°

ANS: E PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: bond angle MSC: general chemistry

25. For which of the following molecules or ions do the electron pairs on the central nitrogen

atom have a tetrahedral arrangement? A) FNO B) NF2

– C) N2F2 D) NO2

– E) NO–

ANS: B PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | tetrahedral arrangement

MSC: general chemistry

26. The molecular geometry of the nitrite ion, NO2

– , is best described as

A) pyramidal. B) trigonal pyramidal. C) bent. D) tetrahedral. E) trigonal planar.

ANS: C PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | trigonal planar arrangement MSC: general chemistry

27. Which molecule does not have a planar molecular geometry?

A) SO3 B) HCCH C) N2H4 D) HNNH E) C2F4

ANS: C PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model MSC: general chemistry

28. Which molecule or ion does not have a planar molecular geometry?

A) NO3–

B) BF3 C) F2CO D) C2H4 E) SO3

2–


29. The molecular geometry of the CH3

+ ion is best described as A) trigonal planar. B) pyramidal. C) linear. D) bent. E) tetrahedral.

ANS: A PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | trigonal planar arrangement MSC: general chemistry

30. Which of the following concerning electron pair space requirements and bond angles is/are

correct? 1. Lone pairs of electrons require more space than bonding pairs. 2. Multiple bonds require the same amount of space as single bonds. 3. The HOH bond angle in H2O and the HNH bond angle in NH3 are identical

because the electron arrangements (tetrahedral) are identical. A) 1 only B) 2 only C) 3 only D) 1 and 2 E) 1, 2, and 3

ANS: A PTS: 1 DIF: easy REF: 10.1 OBJ: Space Requirements-VESPR TOP: bonding | molecular geometry

31. The molecular geometry of the ammonium ion, NH4+, is most similar to the molecular

geometry of A) NH3. B) CH4. C) N2H4. D) NH2

–. E) CH3

+.

ANS: B PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | tetrahedral arrangement MSC: general chemistry

32. The molecular geometry of the CH3

– ion is A) tetrahedral. B) square planar. C) square pyramidal. D) trigonal planar. E) trigonal pyramidal.

ANS: E PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | tetrahedral arrangement MSC: general chemistry

33. What is the molecular geometry of the thiosulfate ion, S2O3

2–? A) tetrahedral B) trigonal bipyramidal C) pyramidal D) bent

E) square planar

ANS: A PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | tetrahedral arrangement MSC: general chemistry

34. Which molecule or ion does not have a trigonal pyramidal molecular geometry?

A) AsF3 B) NF3 C) PF3 D) BF3 E) IO3

–



A) CO32–

B) Cl2CCCl2 C) HNNH D) H3O

+ E) F2CO

ANS: D PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model MSC: general chemistry

36. In phosgene, COCl2, the electron groups are located about the central carbon atom in a

______________ arrangement. A) square planar B) trigonal bipyramidal C) pyramidal D) trigonal planar E) tetrahedral

ANS: D PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | trigonal planar arrangement MSC: general chemistry

37. In the hydronium ion, H3O

+, the electron groups are arranged about the central oxygen atom in a A) tetrahedron. B) square plane.

C) pyramid. D) trigonal plane. E) bent structure.

ANS: A PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | tetrahedral arrangement MSC: general chemistry

38. What is the C—C—H bond angle in H2CCO?

A) 109° B) 180° C) 120° D) 144° E) 90°

ANS: C PTS: 1 DIF: moderate REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: bond angle MSC: general chemistry

39. Which molecule or ion has the same molecular geometry as SeO3

2–? A) SeO3 B) CO3

2– C) NO3

– D) SO3

2– E) SO3

ANS: D PTS: 1 DIF: moderate REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | trigonal planar arrangement MSC: general chemistry

40. Which molecule or ion has the same molecular geometry for its central atom(s) as BF3?

A) CF4 B) CH3

– C) BF4

– D) C2F4 E) C2F6

ANS: D PTS: 1 DIF: moderate REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | trigonal planar arrangement MSC: general chemistry

41. What is the molecular geometry around carbon atom C1?

A) tetrahedral B) trigonal planar C) linear D) trigonal pyramidal E) bent

ANS: B PTS: 1 DIF: moderate REF: 10.1 OBJ: Predict the molecular geometry in a molecule. TOP: bonding | molecular geometry

42. What is the molecular geometry around the nitrogen atom?

A) trigonal pyramidal B) bent C) tetrahedral D) see-saw or distorted tetrahedral E) trigonal planar

ANS: A PTS: 1 DIF: moderate REF: 10.1 OBJ: Predict the molecular geometry in a molecule. TOP: bonding | molecular geometry

43. What is the molecular geometry of the bromate ion, BrO3

–? A) square planar B) trigonal planar C) square pyramidal D) tetrahedral E) trigonal pyramidal

ANS: E PTS: 1 DIF: moderate REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | tetrahedral arrangement MSC: general chemistry

44. Which of the following statements correctly describes the reaction of BF3 with NH3 to form F3B–NH3? A) Both nitrogen and boron change from trigonal planar to tetrahedral geometry

during the reaction. B) Boron changes from trigonal planar to tetrahedral geometry during the reaction. C) There are no changes in the formal charge on any atom during the reaction. D) Nitrogen changes from trigonal planar to tetrahedral geometry during the reaction. E) There is no change in geometry around the nitrogen or boron atoms.

ANS: B PTS: 1 DIF: moderate REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model MSC: general chemistry

45. Which of the following characteristics does not apply to PF3?

A) has three σ bonds B) contains polar bonds C) polar molecule D) one lone pair of electrons on phosphorus E) trigonal planar

ANS: E PTS: 1 DIF: moderate REF: 10.1 OBJ: Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | tetrahedral arrangement MSC: general chemistry

46. What is the H—C—C bond angle in ethylene, H2CCH2?

A) slightly less than 120° B) 90° C) 109° D) 120° E) 180°

ANS: A PTS: 1 DIF: easy REF: 10.1 OBJ: Note that a lone pair tends to require more space than a corresponding bonding pair and that a multiple bond requires more space than a single bond. TOP: bonding | molecular geometry KEY: bond angle MSC: general chemistry

47. What is the H—O—H bond angle in water?

A) 90° B) slightly less than 109° C) 180° D) 120° E) 109°

ANS: B PTS: 1 DIF: easy REF: 10.1 OBJ: Note that a lone pair tends to require more space than a corresponding bonding pair and that a multiple bond requires more space than a single bond. TOP: bonding | molecular geometry KEY: bond angle MSC: general chemistry

48. In the ICI4– ion, how many electron groups surround the central iodine atom?

A) 2 B) 4 C) 5 D) 6 E) 3

ANS: D PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (five or six electron pairs). (Example 10.2) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | octahedral arrangement MSC: general chemistry

49. In the I3

– ion, how many electron groups surround the central atom? A) 5 B) 3 C) 6 D) 4 E) 2

ANS: A PTS: 1 DIF: easy REF: 10.1 OBJ: Predict the molecular geometry (five or six electron pairs). (Example 10.2) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | trigonal bipyramidal arrangement MSC: general chemistry

50. In the ICl4

– ion, the electron pairs are arranged around the central iodine atom in the shape of A) a tetrahedron. B) an octahedron. C) a square plane. D) a trigonal bipyramid. E) a trigonal pyramid.

ANS: B PTS: 1 DIF: moderate REF: 10.1 OBJ: Predict the molecular geometry (five or six electron pairs). (Example 10.2) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | octahedral arrangement MSC: general chemistry

51. In ClF3, the electron pairs are arranged about the chlorine atom in

A) a square plane. B) a tetrahedron. C) an octahedron. D) a trigonal pyramid. E) a trigonal bipyramid.

ANS: E PTS: 1 DIF: moderate REF: 10.1 OBJ: Predict the molecular geometry (five or six electron pairs). (Example 10.2) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | trigonal bipyramidal arrangement


52. What is the molecular geometry of the ICl4

– ion? A) octahedral B) pentagonal C) tetrahedral D) rectangular E) square planar

ANS: E PTS: 1 DIF: moderate REF: 10.1 OBJ: Predict the molecular geometry (five or six electron pairs). (Example 10.2) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model | octahedral arrangement MSC: general chemistry

53. Which molecule or ion does not have a tetrahedral molecular geometry?

A) ClF4–

B) SiF4 C) NF4

+ D) CF4 E) BF4

–

ANS: A PTS: 1 DIF: moderate REF: 10.1 OBJ: Predict the molecular geometry (five or six electron pairs). (Example 10.2) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model MSC: general chemistry


A) BF4–

B) NF4+

C) GeF4 D) XeF4 E) BeF4

2–

ANS: D PTS: 1 DIF: moderate REF: 10.1 OBJ: Predict the molecular geometry (five or six electron pairs). (Example 10.2) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model MSC: general chemistry


A) ICl4–

B) CCl4 C) GeCl4 D) BrO4

– E) SiCl4

ANS: A PTS: 1 DIF: moderate REF: 10.1 OBJ: Predict the molecular geometry (five or six electron pairs). (Example 10.2) TOP: bonding | molecular geometry KEY: the valence-shell electron-pair repulsion model MSC: general chemistry

56. For which molecule or ion does the nitrogen atom have the positive end of the dipole moment? A) NH4

+ B) CN− C) NO D) HCN E) N2

ANS: C PTS: 1 DIF: easy REF: 10.2 OBJ: Explain the relationship between dipole moment and molecular geometry. (Example 10.3) TOP: bonding | molecular geometry KEY: dipole moment MSC: general chemistry

57. Which of the following molecules is nonpolar?

A)

B)

C)

D)

E)

ANS: E PTS: 1 DIF: easy REF: 10.2 OBJ: Explain the relationship between dipole moment and molecular geometry. (Example 10.3) TOP: bonding | molecular geometry KEY: dipole moment MSC: general chemistry

58. Which molecule is polar?

A) C2H4 B) CS2 C) C6H6 D) SO2 E) CF4

ANS: D PTS: 1 DIF: easy REF: 10.2 OBJ: Explain the relationship between dipole moment and molecular geometry. (Example 10.3) TOP: bonding | molecular geometry KEY: dipole moment MSC: general chemistry

59. Which of the following concerning molecular geometry and dipole moments is/are correct?

1. Only molecules with polar bonds may have a permanent dipole moment. 2. All molecules with polar bonds have a permanent dipole moment. 3. All square planar molecules are nonpolar. A) 1 only B) 2 only C) 3 only D) 1 and 3 E) 1, 2, and 3

ANS: A PTS: 1 DIF: easy REF: 10.2 OBJ: Explain the relationship between dipole moment and molecular geometry. (Example 10.3) TOP: bonding | molecular geometry

60. Which of the following molecules has a permanent dipole moment?

A) SF6 B) CCl4 C) NF3 D) SiCl4 E) BF3

ANS: C PTS: 1 DIF: easy REF: 10.2 OBJ: Explain the relationship between dipole moment and molecular geometry. (Example 10.3) TOP: bonding | molecular geometry KEY: dipole moment MSC: general chemistry

61. Which of the following molecules does not have a permanent dipole moment?

A) sulfur tetrafluoride, SF4 B) iodine trichloride, ICl3 C) nitrogen trifluoride, NF3 D) phosphorus pentafluoride, PF5 E) sulfur dioxide, SO2

ANS: D PTS: 1 DIF: easy REF: 10.2 OBJ: Explain the relationship between dipole moment and molecular geometry. (Example 10.3) TOP: bonding | molecular geometry

62. Which of the following molecules has a dipole moment?

A) PF5 B) FOOF C) HCCH D) F2CCF2 E) SF6

ANS: B PTS: 1 DIF: easy REF: 10.2 OBJ: Explain the relationship between dipole moment and molecular geometry. (Example 10.3) TOP: bonding | molecular geometry KEY: dipole moment MSC: general chemistry

63. Which of the following molecules has a dipole moment?

A) SO2 B) CS2 C) ClCCCCCl D) CCl4 E) HCCH

ANS: A PTS: 1 DIF: easy REF: 10.2 OBJ: Explain the relationship between dipole moment and molecular geometry. (Example 10.3) TOP: bonding | molecular geometry KEY: dipole moment MSC: general chemistry

64. Which of the following compounds is nonpolar?

A) H2S B) XeF2 C) SO2 D) N2O E) HCl

ANS: B PTS: 1 DIF: easy REF: 10.2 OBJ: Explain the relationship between dipole moment and molecular geometry. (Example 10.3) TOP: bonding | molecular geometry KEY: dipole moment MSC: general chemistry

65. Which of the following molecules is polar?

A) SF6 B) CCl4 C) BF3 D) NO2 E) CO2

ANS: D PTS: 1 DIF: easy REF: 10.2 OBJ: Explain the relationship between dipole moment and molecular geometry. (Example 10.3) TOP: bonding | molecular geometry KEY: dipole moment MSC: general chemistry

66. Which of the following statements best describes N2O?

A) The molecular geometry is bent and the molecule is nonpolar. B) The molecular geometry is linear and the molecule is nonpolar. C) The molecular geometry is linear and the molecule is polar. D) The molecular geometry is trigonal planar and the molecule is nonpolar. E) The molecular geometry is bent and the molecule is polar.

ANS: C PTS: 1 DIF: moderate REF: 10.2 OBJ: Explain the relationship between dipole moment and molecular geometry. (Example

10.3) TOP: bonding | molecular geometry KEY: dipole moment MSC: general chemistry

67. Which of the following molecules is nonpolar?

A) SF4 B) PF5 C) ClF3 D) PF3 E) CH2F2

ANS: B PTS: 1 DIF: moderate REF: 10.2 OBJ: Explain the relationship between dipole moment and molecular geometry. (Example 10.3) TOP: bonding | molecular geometry KEY: dipole moment MSC: general chemistry

68. Which one of the following statements provides the best evidence that all the carbon

compounds listed below have tetrahedral molecular geometries instead of square planar molecular geometries? A) Only one CH4 compound is known and it is nonpolar. B) Only one CH3F compound is known and it is polar. C) Only one CH2F2 compound is known and it is polar. D) Only one CF4 compound is known and it is nonpolar. E) Only one CHF3 compound is known and it is polar.

ANS: C PTS: 1 DIF: difficult REF: 10.2 OBJ: Explain the relationship between dipole moment and molecular geometry. (Example 10.3) TOP: bonding | molecular geometry KEY: dipole moment MSC: general chemistry

69. When an atom in a molecule or ion is described as sp3d2 hybridized, its molecular geometry

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

ANS: A PTS: 1 DIF: easy REF: 10.3 OBJ: Apply valence bond theory (two, three, or four electron pairs). (Example 10.4) TOP: bonding | bonding theories

70. How many sigma and pi bonds are in the molecule pictured below?

A) thirteen sigma bonds and one pi bond

B) eleven sigma bonds and two pi bonds C) thirteen sigma bonds and two pi bonds D) eleven sigma bonds and five pi bonds E) five sigma bonds and eleven pi bonds

ANS: A PTS: 1 DIF: easy REF: 10.3 OBJ: Apply valence bond theory (two, three, or four electron pairs). (Example 10.4) TOP: bonding | bonding theories

71. What hybrid orbitals of sulfur are involved in the bonding in sulfur trioxide?

A) sp2 B) sp2d C) sp3 D) sp3d2 E) sp

ANS: A PTS: 1 DIF: moderate REF: 10.3 OBJ: Apply valence bond theory (two, three, or four electron pairs). (Example 10.4) TOP: bonding | bonding theories KEY: hybridization MSC: general chemistry

72. Which of the following statements is incorrect regarding the water molecule?

A) There are two lone pairs and two bonding pairs on the central atom. B) The molecule is polar. C) The hybridization of oxygen is sp3. D) The hybridization of hydrogen is sp. E) The molecular geometry is bent.

ANS: D PTS: 1 DIF: moderate REF: 10.3 OBJ: Apply valence bond theory (two, three, or four electron pairs). (Example 10.4) TOP: bonding | bonding theories KEY: hybridization MSC: general chemistry

73. What is the hybridization of Se in SeF6?

A) sp3d B) sp3d2 C) sp2 D) sp E) sp3

ANS: B PTS: 1 DIF: easy REF: 10.3 OBJ: Apply valence bond theory (five or six electron pairs). (Example 10.5) TOP: bonding | bonding theories KEY: hybridization MSC: general chemistry

74. What is the hybridization of Br in BrF3?

A) sp3 B) sp C) sp3d2 D) sp2 E) sp3d

ANS: E PTS: 1 DIF: easy REF: 10.3 OBJ: Apply valence bond theory (five or six electron pairs). (Example 10.5) TOP: bonding | bonding theories KEY: hybridization MSC: general chemistry

75. What is the hybridization of I in IF4

–? A) sp2 B) sp C) sp3d D) sp3d2 E) sp3

ANS: D PTS: 1 DIF: easy REF: 10.3 OBJ: Apply valence bond theory (five or six electron pairs). (Example 10.5) TOP: bonding | bonding theories KEY: hybridization MSC: general chemistry

76. According to valence-bond theory, what is the hybridization scheme of the sulfur atom in

SF4? A)

B)

C)

D)

E)

ANS: C PTS: 1 DIF: easy REF: 10.3 OBJ: Apply valence bond theory (five or six electron pairs). (Example 10.5) TOP: bonding | bonding theories KEY: hybridization


77. A π bond is the result of the

A) overlap of two s orbitals. B) overlap of two p orbitals along their axes. C) sideways overlap of two parallel p orbitals. D) overlap of an s orbital and a p orbital. E) sideways overlap of two s orbitals.

ANS: C PTS: 1 DIF: easy REF: 10.4 OBJ: Define pi bond. TOP: bonding | bonding theories KEY: multiple bonding MSC: general chemistry

78. Which of the following statements is true?

A) A π bond is twice as strong as a single bond. B) A π bond results from the sideways overlap of hybridized orbitals. C) A double bond consists of a π bond and a σ bond. D) A π bond has cylindrical symmetry about the bonding axis. E) A π bond is twice as strong as a σ bond.

ANS: C PTS: 1 DIF: moderate REF: 10.4 OBJ: Define pi bond. TOP: bonding | bonding theories KEY: multiple bonding MSC: general chemistry

79. Which of the labeled carbons (C1-C4) is/are sp3-hybridized?

A) carbon two and four B) carbon three C) carbon one D) carbon two E) carbon one and three

ANS: A PTS: 1 DIF: easy REF: 10.4 OBJ: Apply valence bond theory (multiple bonding). (Example 10.6) TOP: bonding | bonding theories

80. What is the hybridization of the nitrogen atom in the nitrite ion?

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

ANS: E PTS: 1 DIF: moderate REF: 10.4 OBJ: Apply valence bond theory (multiple bonding). (Example 10.6) TOP: bonding | bonding theories KEY: multiple bonding MSC: general chemistry

81. According to valence-bond theory, the bonding in ketene, H2CCO, is best described as

A) five π bonds. B) three σ bonds and two π bonds. C) four σ bonds and two π bonds. D) four σ bonds and one π bond. E) five σ bonds.

ANS: C PTS: 1 DIF: moderate REF: 10.4 OBJ: Apply valence bond theory (multiple bonding). (Example 10.6) TOP: bonding | bonding theories KEY: multiple bonding MSC: general chemistry

82. Which of the following concerning σ and π bonds is/are correct?

1. Sigma bonds may only be formed from unhybridized orbitals. 2. Pi bonds are formed from unhybridized p orbitals. 3. A pi bond has an electron distribution above and below the bond axis. A) 1 only B) 2 only C) 3 only D) 1 and 2 E) 2 and 3

ANS: E PTS: 1 DIF: moderate REF: 10.4 OBJ: Apply valence bond theory (multiple bonding). (Example 10.6) TOP: bonding | bonding theories NOT: REVISED

83. Which of the following concerning σ and π bonds is/are correct?

1. A sigma bond may be formed from the sideways overlap of two parallel p

orbitals. 2. No more than two pi bonds are possible between adjacent carbon atoms. 3. The considerable energy required to rotate pi bonded atoms is the primary

reason for geometrical isomerism in some pi bonded molecules. A) 1 only B) 2 only C) 3 only D) 1 and 2 E) 2 and 3

ANS: E PTS: 1 DIF: moderate REF: 10.4 OBJ: Apply valence bond theory (multiple bonding). (Example 10.6) TOP: bonding | bonding theories

84. Which molecule or ion does not contain two π bonds?

A) HCCH B) H2CCCH2 C) NO– D) CS2 E) SCN–

ANS: C PTS: 1 DIF: moderate REF: 10.4 OBJ: Apply valence bond theory (multiple bonding). (Example 10.6) TOP: bonding | bonding theories KEY: multiple bonding MSC: general chemistry

85. If four orbitals on one atom overlap four orbitals on a second atom, how many molecular

orbitals will form? A) 4 B) 16 C) 1 D) 8 E) none of these

ANS: D PTS: 1 DIF: moderate REF: 10.5 OBJ: Define molecular orbital theory. TOP: bonding | bonding theories KEY: molecular orbital theory MSC: general chemistry

86. Which of the following statements is/are true?

1. Electrons are never found in an antibonding molecular orbital. 2. Antibonding molecular orbitals have electron density mainly outside the space

between the two nuclei. 3. All antibonding molecular orbitals are higher in energy than the atomic

orbitals of which they are composed. A) 1 only B) 2 only C) 3 only D) 1 and 2 E) 2 and 3

ANS: E PTS: 1 DIF: moderate REF: 10.5 OBJ: Define bonding orbitals and antibonding orbitals. TOP: bonding | bonding theories KEY: molecular orbital theory MSC: general chemistry

87. The nitrosyl ion, NO+, has ten bonding electrons and four antibonding electrons. Therefore,

it has a bond order of A) 1. B) 5/2. C) 7. D) 2.

E) 3.

ANS: E PTS: 1 DIF: easy REF: 10.5 OBJ: Define bond order. TOP: bonding | bonding theories KEY: molecular orbital theory | bond order MSC: general chemistry

88. Which of the following species has(have) a bond order of 2?

1. NO–

2. O2

3. O2–

A) 1 only B) 3 only C) 2 only D) 1 and 3 E) 1 and 2

ANS: E PTS: 1 DIF: moderate REF: 10.5 OBJ: Define bond order. TOP: bonding | bonding characteristics KEY: molecular orbital theory | bond order MSC: general chemistry

89. Which of the following species has a bond order of 2.5?

A) N2 B) NO+ C) CO D) O2

+ E) NO–

ANS: D PTS: 1 DIF: moderate REF: 10.5 OBJ: Define bond order. TOP: bonding | bonding theories KEY: molecular orbital theory | bond order MSC: general chemistry

90. Which molecule or ion has a bond order of 2.5?

A) O2 B) O2

+ C) NO– D) O2

2– E) O2

–

ANS: B PTS: 1 DIF: moderate REF: 10.5 OBJ: Define bond order. TOP: bonding | bonding theories KEY: molecular orbital theory | bond order MSC: general chemistry

91. Which of the following species has(have) a bond order of 1?

1. HF 2. O2

2− 3. O2

2+

A) 1 only B) 3 only C) 1 and 2 D) 2 and 3 E) 2 only

ANS: C PTS: 1 DIF: moderate REF: 10.5 OBJ: Define bond order. TOP: bonding | bonding theories KEY: molecular orbital theory | bond order MSC: general chemistry

92. Given the molecular orbital diagram for dilithium (Li2) below, what would be the bond

order of Li2+?

A)

B)

C) 1 D) 0 E) 2

ANS: A PTS: 1 DIF: moderate REF: 10.5 OBJ: Describe the electron configurations of H2, He2, Li2, and Be2. TOP: bonding | bonding theories

93. Which of the following statements is not correct?

A) Hybrid orbitals are made by the combination of atomic orbitals on a given atom. B) In both valence bond theory and molecular orbital theory bonding result from the

overlap of occupied atomic orbitals. C) Valence bond theory does not account for the experimentally observed

paramagnetism of molecules like O2.

D) Pi bonds may be formed from s or p orbital overlap. E) In molecular orbital theory a molecular orbital may encompass more than two

atoms.

ANS: D PTS: 1 DIF: easy REF: 10.6 OBJ: Describe molecular orbital configurations (homonuclear diatomic molecules). (Example 10.7) TOP: bonding | bonding theories KEY: molecular orbital theory MSC: general chemistry

94. Given the molecular orbital diagram for dinitrogen (N2) excluding the K shells below, which

of the following molecules or ions is expected to be diamagnetic?

A) C2

2– B) O2 C) B2 D) O2

– E) O2

+

ANS: A PTS: 1 DIF: moderate REF: 10.6 OBJ: Describe molecular orbital configurations (homonuclear diatomic molecules). (Example 10.7) TOP: bonding | bonding theories NOT: REVISED

95. Which molecule or ion has the highest bond order?

A) F2–

B) O2 C) O2

2– D) N2 E) F2

ANS: D PTS: 1 DIF: moderate REF: 10.6 OBJ: Describe molecular orbital configurations (homonuclear diatomic molecules). (Example 10.7) TOP: bonding | bonding theories KEY: diatomic molecule MSC: general chemistry

96. Given the molecular orbital diagram for dinitrogen (N2) excluding the K shells below and

assuming all species have a similar ordering of their MO’s, which of the following would be expected to be diamagnetic?

A) O2 B) F2

− C) O2

2− D) B2 E) Li2

+

ANS: C PTS: 1 DIF: moderate REF: 10.6 OBJ: Describe molecular orbital configurations (homonuclear diatomic molecules). (Example 10.7) TOP: bonding | bonding theories NOT: REVISED

97. Consider the following series of molecular ions and molecules: F2

+, F22+, F2, and F2

–. Which will have the shortest bond length between the fluorine atoms? Assume the homonuclear molecular orbital diagram provided below for nitrogen (excluding the K shells) still applies to these species.

A) F2

+ B) The bond lengths are all equivalent. C) F2

2+ D) F2 E) F2

–

ANS: C PTS: 1 DIF: moderate REF: 10.6 OBJ: Describe molecular orbital configurations (homonuclear diatomic molecules). (Example 10.7) TOP: bonding | bonding theories KEY: diatomic molecule MSC: general chemistry

98. The configuration (σ2s)

2(σ2s*)2(π2py)

1(π2px)1 is the molecular orbital description for the

ground state of A) C2. B) B2. C) Be2. D) Li2

+. E) B2

2–.

ANS: B PTS: 1 DIF: difficult REF: 10.6 OBJ: Describe molecular orbital configurations (homonuclear diatomic molecules). (Example 10.7) TOP: bonding | bonding theories KEY: diatomic molecule MSC: general chemistry

99. Which molecule or ion has the shortest bond distance?

A) NO+ B) CO+ C) NO D) NO– E) CO–

ANS: A PTS: 1 DIF: moderate REF: 10.6 OBJ: Describe molecular orbital configurations (heteronuclear diatomic molecules). (Example 10.8) TOP: bonding | bonding theories KEY: diatomic molecule MSC: general chemistry

100. In the molecular orbital description of CO,

A) six molecular orbitals contain electrons. B) there are two unpaired electrons. C) the bond order is 3. D) the highest-energy electrons occupy antibonding orbitals. E) All of the above are false.

ANS: C PTS: 1 DIF: moderate REF: 10.6 OBJ: Describe molecular orbital configurations (heteronuclear diatomic molecules). (Example 10.8) TOP: bonding | bonding theories KEY: diatomic molecule MSC: general chemistry

101. Which of the following electron distributions among the molecular orbitals best describes

the NO molecule?

σ2s σ2s

* π2py=π2px σ2pz

π2py*=π2px

* σ2pz*

A) 2 2 4 1 3 0 B) 2 2 4 2 4 1 C) 2 2 4 2 1 0 D) 2 2 4 2 2 0 E) 2 2 4 2 4 2

ANS: C PTS: 1 DIF: difficult REF: 10.6 OBJ: Describe molecular orbital configurations (heteronuclear diatomic molecules).

(Example 10.8) TOP: bonding | bonding theories KEY: diatomic molecule MSC: general chemistry

102. Which of the following statements about the molecule O2 is false?

A) Its bond order is 2. B) The total number of electrons is 12. C) It is paramagnetic. D) It has two pi bonds. E) It has one sigma bond.

ANS: D PTS: 1 DIF: moderate REF: 10.6 OBJ: Describe molecular orbital configurations (heteronuclear diatomic molecules). (Example 10.8) TOP: bonding | bonding theories KEY: diatomic molecule MSC: general chemistry

103. Which molecule or ion is paramagnetic?

A) NO2+

B) OCN– C) NO2

– D) NO E) SO3

ANS: D PTS: 1 DIF: moderate REF: 10.6 OBJ: Describe molecular orbital configurations (heteronuclear diatomic molecules). (Example 10.8) TOP: bonding | bonding theories KEY: diatomic molecule MSC: general chemistry

104. Which of the following statements concerning ozone is incorrect?

A) It is generated by passing an electrical discharge through oxygen. B) It has a partial double-bond character. C) It is a nonpolar molecule. D) It is an important absorber of ultraviolet radiation in the stratosphere. E) It has a bond angle similar to that predicted for sp2 hybridization.

ANS: C PTS: 1 DIF: easy REF: 10.7 OBJ: Describe the delocalized bonding in molecules such as O3. TOP: bonding | bonding theories KEY: molecular orbital and delocalized bonding MSC: general chemistry

105. Which of these statements about benzene is true?

A) Benzene is an example of a molecule that displays ionic bonding. B) Benzene contains only π bonds between C atoms. C) All carbon atoms in benzene are sp3 hybridized. D) The bond order of each C—C bond in benzene is 1.5. E) All of these statements are false.

ANS: D PTS: 1 DIF: moderate REF: 10.7 OBJ: Describe the delocalized bonding in molecules such as O3. TOP: bonding | bonding theories KEY: molecular orbital and delocalized bonding MSC: general chemistry

106. The following statements concern molecules that require resonance. Which is true? A) The benzene molecule is best described by the MO theory. B) The sigma bonding is clearly delocalized. C) Both the sigma bonding and the pi bonding are delocalized. D) The benzene molecule is best described by the localized electron model. E) The pi bonding is clearly delocalized.

ANS: E PTS: 1 DIF: moderate REF: 10.7 OBJ: Describe the delocalized bonding in molecules such as O3. TOP: bonding | bonding theories KEY: molecular orbital and delocalized bonding MSC: general chemistry

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