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Chapter 10 - Molecular Geometry and Chemical Bonding Theory 1. Which molecule or ion does not have a trigonal pyramidal molecular geometry? – A) PO3 – B) SO3 C) NI3 D) BF3 E) XeO3 ANS: OBJ: TOP: KEY: MSC:

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

2. What is the electron geometry 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: OBJ: Electron Geometry-4 Geometr y-4 electron pairs TOP: bonding | molecular geometry

easy

REF: 10.1

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: OBJ: Molecular Geometry-4 Geometr y-4 electron pairs TOP: bonding | molecular geometry

easy

REF: 10.1

4. What is the molecular geometry around an atom in a molecule or ion which is surrounded 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 ANS: A PTS: 1 DIF: OBJ: Molecular Geometry-5 Geometr y-5 electron pairs TOP: bonding | molecular geometry

easy

REF: 10.1

5. What is the electron geometry geometry (or electron arrangement) around an atom in a molecule or 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 ANS: A PTS: 1 DIF: OBJ: Electron Geometry-5 Geometr y-5 electron pairs TOP: bonding | molecular geometry

easy

REF: 10.1

6. What is the electron geometry geometry (or electron arrangement) around an atom in a molecule or 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 ANS: A PTS: 1 DIF: OBJ: Electron Geometry-6 Geometr y-6 electron pairs TOP: bonding | molecular geometry

easy

REF: 10.1

7. What is the molecular geometry around an atom in a molecule or ion which is surrounded 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: OBJ: Molecular Geometry-2-6 Geometr y-2-6 bonding pair TOP: bonding | molecular geometry

easy

REF: 10.1

8. What is the molecular geometry around an atom in a molecule or ion which is surrounded by zero lone pairs of electrons and six single bonds. A) octahedral B) square planar C) square pyramidal D) bent E) linear ANS: A PTS: 1 DIF: OBJ: Molecular Geometry-6 Geometr y-6 electron pairs TOP: bonding | molecular geometry

easy

9. Which molecule or ion has a trigonal planar molecular geometry? A) PCl3

REF: 10.1

B) C) D) E)

HCN – CO3 HCCH AsF3

ANS: OBJ: TOP: KEY: MSC:

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

10. Which molecule or ion has a trigonal pyramidal molecular geometry? A) H2CO B) H2CCO + C) CH3 – D) CH3 E) C2H4 ANS: OBJ: TOP: KEY: MSC:

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

11. Which molecule or ion is not planar? A) H2CO – B) NO2 C) C2F4 D) H2CCO – E) PO4 ANS: OBJ: TOP: KEY:

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

12. Which molecule or ion is not planar? A) XeF4 – B) NO3 C) BCl3 D) F2CCF2 E) CF4 ANS: OBJ: TOP: KEY:

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

13. Which molecule or ion has a trigonal pyramidal molecular geometry? A) BF3 B) C2H4

C) SO3 – D) SO3 – E) CO3 ANS: OBJ: TOP: KEY: MSC:


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: OBJ: TOP: KEY: MSC:

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

15. Which molecule or ion is nonlinear? A) CO2 – B) NF2 C) OCN– + D) NO2 E) HCCH ANS: OBJ: TOP: KEY:

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

16. Which molecule or ion is nonlinear? A) N2O B) O3 – C) OCN + D) NO2 E) CS2 ANS: OBJ: TOP: KEY:


17. Which molecule or ion is nonlinear? + A) NO2 B) SO2

C) NNO D) CS2 – E) SCN ANS: OBJ: TOP: KEY:


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

, is

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 CH 3 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, C 2H6, 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: OBJ: TOP: KEY: MSC:

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

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

MSC: general chemistry –

26. The molecular geometry of the nitrite ion, NO 2 , is best described as A) pyramidal. B) trigonal pyramidal. C) bent. D) tetrahedral. E) trigonal planar. ANS: OBJ: TOP: KEY: MSC:

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

27. Which molecule does not have a planar molecular geometry? A) SO3 B) HCCH C) N2H4 D) HNNH E) C2F4 ANS: OBJ: TOP: KEY:

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

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

29. The molecular geometry of the CH 3 ion is best described as A) trigonal planar. B) pyramidal. C) linear. D) bent. E) tetrahedral. ANS: OBJ: TOP: KEY: MSC:

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

30. Which of the following concerning electron pair space requirements and bond angles is/are correct? 1. 2. 3.

A) B) C) D) E)

Lone pairs of electrons require more space than bonding pairs. Multiple bonds require the same amount of space as single bonds. The HOH bond angle in H2O and the HNH bond angle in NH 3 are identical because the electron arrangements (tetrahedral) are identical.

1 only 2 only 3 only 1 and 2 1, 2, and 3

ANS: A PTS: 1 OBJ: Space Requirements-VESPR

DIF: easy REF: 10.1 TOP: bonding | molecular geometry +

31. The molecular geometry of the ammonium ion, NH 4 , is most similar to the molecular geometry of A) NH3. B) CH4. C) N2H4. – D) NH2 . + E) CH3 . ANS: OBJ: TOP: KEY: MSC:

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

32. The molecular geometry of the CH 3 ion is A) tetrahedral. B) square planar. C) square pyramidal. D) trigonal planar. E) trigonal pyramidal. ANS: OBJ: TOP: KEY: MSC:

E PTS: 1 DIF: easy REF: 10.1 Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) bonding | molecular geometry the valence-shell electron-pair repulsion model | tetrahedral arrangement general chemistry 2–

33. What is the molecular geometry of the thiosulfate ion, S 2O3 ? A) tetrahedral B) trigonal bipyramidal C) pyramidal D) bent

E) square planar ANS: OBJ: TOP: KEY: MSC:

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


35. Which molecule or ion is not planar? – A) CO3 B) Cl2CCCl2 C) HNNH + D) H3O E) F2CO ANS: OBJ: TOP: KEY:

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

36. In phosgene, COCl 2, 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: OBJ: TOP: KEY: MSC:

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

37. In the hydronium ion, H 3O , 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: OBJ: TOP: KEY: MSC:

A PTS: 1 DIF: easy REF: 10.1 Predict the molecular geometry (two, three, or four electron pairs). (Example 10.1) bonding | molecular geometry the valence-shell electron-pair repulsion model | tetrahedral arrangement 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 2–

39. Which molecule or ion has the same molecular geometry as SeO 3 ? A) SeO3 – B) CO3 – C) NO3 – D) SO3 E) SO3 ANS: OBJ: TOP: KEY: MSC:

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

40. Which molecule or ion has the same molecular geometry for its central atom(s) as BF 3? A) CF4 – B) CH3 – C) BF4 D) C2F4 E) C2F6 ANS: OBJ: TOP: KEY: MSC:

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

41. What is the molecular geometry around carbon atom C 1?

A) B) C) D) E)

tetrahedral trigonal planar linear trigonal pyramidal bent

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

REF: 10.1

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

A) B) C) D) E)

trigonal pyramidal bent tetrahedral see-saw or distorted tetrahedral trigonal planar

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

REF: 10.1

–

43. What is the molecular geometry of the bromate ion, BrO 3 ? A) square planar B) trigonal planar C) square pyramidal D) tetrahedral E) trigonal pyramidal ANS: OBJ: TOP: KEY: MSC:

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

44. Which of the following statements correctly describes the reaction of BF 3 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: OBJ: TOP: KEY:

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

45. Which of the following characteristics does not apply to PF 3? A) has three σ bonds B) contains polar bonds C) polar molecule D) one lone pair of electrons on phosphorus E) trigonal planar ANS: OBJ: TOP: KEY: MSC:

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

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

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

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

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

MSC: general chemistry –

52. What is the molecular geometry of the ICl4 ion? A) octahedral B) pentagonal C) tetrahedral D) rectangular E) square planar ANS: OBJ: TOP: KEY: MSC:

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

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

54. Which molecule or ion does not have a tetrahedral molecular geometry? – A) BF4 + B) NF4 C) GeF4 D) XeF4 – E) BeF4 ANS: OBJ: TOP: KEY:

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

55. Which molecule or ion does not have a tetrahedral molecular geometry? – A) ICl4 B) CCl4 C) GeCl4 – D) BrO4 E) SiCl4 ANS: OBJ: TOP: KEY:

A PTS: 1 DIF: moderate REF: 10.1 Predict the molecular geometry (five or six electron pairs). (Example 10.2) bonding | molecular geometry 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: OBJ: 10.3) KEY:

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

57. Which of the following molecules is nonpolar? A)

B)

C)

D)

E)

ANS: OBJ: 10.3) KEY:

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

58. Which molecule is polar? A) C2H4 B) CS2 C) C6H6 D) SO2 E) CF4


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

59. Which of the following concerning molecular geometry and dipole moments is/are correct? 1. 2. 3. A) B) C) D) E)

Only molecules with polar bonds may have a permanent dipole moment. All molecules with polar bonds have a permanent dipole moment. All square planar molecules are nonpolar.

1 only 2 only 3 only 1 and 3 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: OBJ: 10.3) KEY:

C PTS: 1 DIF: easy REF: 10.2 Explain the relationship between dipole moment and molecular geometry. (Example TOP: bonding | molecular geometry 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, ICl 3 C) nitrogen trifluoride, NF 3 D) phosphorus pentafluoride, PF 5 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


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

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

64. Which of the following compounds is nonpolar? A) H2S B) XeF2 C) SO2 D) N2O E) HCl ANS: OBJ: 10.3) KEY:

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

65. Which of the following molecules is polar? A) SF6 B) CCl4 C) BF3 D) NO2 E) CO2 ANS: OBJ: 10.3) KEY:

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

66. Which of the following statements best describes N 2O? 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: OBJ: 10.3) KEY:

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

C PTS: 1 DIF: difficult REF: 10.2 Explain the relationship between dipole moment and molecular geometry. (Example TOP: bonding | molecular geometry dipole moment MSC: general chemistry 3 2

69. When an atom in a molecule or ion is described as sp d 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) C) D) E)

eleven sigma bonds and two pi bonds thirteen sigma bonds and two pi bonds eleven sigma bonds and five pi bonds 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) sp B) sp d C) sp D) sp d E) sp ANS: OBJ: TOP: MSC:

A PTS: 1 DIF: moderate REF: 10.3 Apply valence bond theory (two, three, or four electron pairs). (Example 10.4) bonding | bonding theories KEY: hybridization 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 sp . D) The hybridization of hydrogen is sp. E) The molecular geometry is bent. ANS: OBJ: TOP: MSC:

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

73. What is the hybridization of Se in SeF6? A) sp d B) sp d C) sp D) sp E) sp ANS: OBJ: TOP: MSC:

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

74. What is the hybridization of Br in BrF 3? A) sp B) sp C) sp d D) sp E) sp d

ANS: OBJ: TOP: MSC:

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

75. What is the hybridization of I in IF4 ? A) sp B) sp C) sp d D) sp d E) sp ANS: OBJ: TOP: MSC:

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

MSC: general chemistry 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: OBJ: Define pi bond. KEY: multiple bonding

1

DIF: easy REF: 10.4 TOP: bonding | bonding theories 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: OBJ: Define pi bond. KEY: multiple bonding

1

DIF: moderate REF: 10.4 TOP: bonding | bonding theories MSC: general chemistry 3

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

A) B) C) D) E)

carbon two and four carbon three carbon one carbon two 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) sp d B) sp C) s D) sp E) sp

ANS: OBJ: TOP: MSC:

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

81. According to valence-bond theory, the bonding in ketene, H 2CCO, 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: OBJ: TOP: MSC:

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

82. Which of the following concerning 1. 2. 3. A) B) C) D) E)

σ and π bonds

is/are correct?

Sigma bonds may only be formed from unhybridized orbitals. Pi bonds are formed from unhybridized p orbitals. A pi bond has an electron distribution above and below the bond axis.

1 only 2 only 3 only 1 and 2 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 1. 2. 3.

A) B) C) D) E)

σ and π bonds

is/are correct?

A sigma bond may be formed from the sideways overlap of two parallel p orbitals. No more than two pi bonds are possible between adjacent carbon atoms. The considerable energy required to rotate pi bonded atoms is the primary reason for geometrical isomerism in some pi bonded molecules.


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: OBJ: TOP: MSC:

C PTS: 1 DIF: moderate REF: 10.4 Apply valence bond theory (multiple bonding). (Example 10.6) bonding | bonding theories KEY: multiple bonding 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 OBJ: Define molecular orbital theory. KEY: molecular orbital theory

DIF: moderate REF: 10.5 TOP: bonding | bonding theories MSC: general chemistry

86. Which of the following statements is/are true? 1. 2. 3.

A) B) C) D) E)

Electrons are never found in an antibonding molecular orbital. Antibonding molecular orbitals have electron density mainly outside the space between the two nuclei. All antibonding molecular orbitals are higher in energy than the atomic orbitals of which they are composed.


ANS: OBJ: TOP: MSC:

E PTS: 1 DIF: moderate REF: 10.5 Define bonding orbitals and antibonding orbitals. bonding | bonding theories KEY: molecular orbital theory 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 – 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− 2. O2 2+ 3. O2 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 (Li 2) below, what would be the bond + order of Li 2 ?

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 O 2. 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 (N 2) excluding the K shells below, which of the following molecules or ions is expected to be diamagnetic?

A) B) C) D) E)

–

C2 O2 B2 – O2 + 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 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 (N 2) 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) B) C) D) E)

O2 − F2 2− O2 B2 + 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 +

2+

–

97. Consider the following series of molecular ions and molecules: F 2 , F2 , 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) B) C) D) E)

+

F2 The bond lengths are all equivalent. + F2 F2 – 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

2

2

1

1

98. The configuration ( σ2s) (σ2s*) (π2py) (π2px) is the molecular orbital description for the ground state of A) C2. B) B2. C) Be2. + D) Li2 . – E) B2 . 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

A) B) C) D) E)

2 2 2 2 2

*

σ2s

π2py=π2px

2 2 2 2 2

σ2pz

4 4 4 4 4

*

π2py

=π2px 1 2 2 2 2

*

σ2pz

*

3 4 1 2 4

0 1 0 0 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 O 2 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 sp hybridization. ANS: OBJ: TOP: KEY:

C PTS: 1 DIF: easy REF: 10.7 Describe the delocalized bonding in molecules such as O3. bonding | bonding theories 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 sp hybridized. D) The bond order of each C—C bond in benzene is 1.5. E) All of these statements are false. ANS: OBJ: TOP: KEY:

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

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