1. Which of the following covalent bonds is the most polar (highest percent ionic character)? A. Al I B. Si I C. Al Cl D. Si Cl E. Si P 2. What is the hybridization of the central atom in ClO 3? A. sp B. sp2 C. sp3 D. sp3d E. sp3d2 3. Which of the following solids would have the lowest melting point? A. KI B. KBr C. KCl D. KF 4. Estimate the enthalpy change, ΔH, for the reaction 2CO + O 2 2CO 2 given the following bond energies. BE(C O) = 1074 kj/mol BE(O=O) = 499 kj/mol BE(C=O) = 802 kj/mol A. +2380 kj B. +744 kj C. +1949 kj D. -561 kj E. -744 kj 5. Which one of the following molecules has an atom with an expanded octet? A. HCl B. AsCl 5 C. ICl D. NCl 3 E. Cl 2 6. How many covalent bonds will a nitrogen atom usually form? A. 1 B. 2 C. 3 D. 5 E. 8 7. Which of the elements listed below has the greatest electronegativity? A. Mg B. Ga C. Si D. Ba E. Pb 8. Which of the atoms listed below is the most electronegative? A. Li B. Cs C. P D. As E. Ge 9. Which one of the following molecules is nonpolar? A. NH 3 B. OF 2 C. CH 3 Cl D. H 2 O E. BeCl 2 10. The geometry of the ClF 3 molecule is best described as: A. distorted tetrahedron B. trigonal planar C. tetrahedral D. T-shaped E. trigonal pyramidal 11. According to the VSEPR, theory the geometry of the atoms in the carbonate ion, CO 3 2 is A. square planar. B. tetrahedral. C. pyramidal. D. trigonal planar. E. octahedral. Page 1
12. Which one of the following compounds does not follow the octet rule? A. NF 3 B. CF 4 C. PF 5 D. AsH 3 E. HCl 13. The bond between which of the following pairs of atoms would be the least polar (lowest percent ionic character)? A. C Cl B. C C C. C H D. O C E. N C 14. The total number of bonding electrons in a molecule of formaldehyde (H 2 CO) is A. 3 B. 4 C. 6 D. 8 E. 18 15. A nonpolar covalent bond (pure covalent) would form between which one of the following pairs of atoms? A. Na Cl B. H Cl C. Li Br D. Se Br E. Br Br 16. What is the hybridization on the central atom in NO 3? A. sp B. sp2 C. sp3 D. sp3d E. sp3d2 18. The Lewis structure for a chlorate ion, ClO 3 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, 10 19. Each of the three resonance structures of NO 3 has how many lone pairs of electrons? A. 7 B. 8 C. 9 D. 10 E. 13 20. According to VSEPR theory, which one of the following molecules should be trigonal bipyramidal? A. SF 4 B. XeF 4 C. NF 3 D. SF 6 E. PF 5 21. The geometry of the CS 2 molecule is best described as A. linear. B. trigonal planar. C. tetrahedral. D. bent. E. trigonal pyramidal. 22. Predict the molecular geometry and polarity of the SO 2 molecule. A. linear, polar B. linear, nonpolar C. bent, polar D. bent, nonpolar E. None of the above. 23. Which one of the following is most likely to be a covalent compound? A. Rb 2 S B. SrCl 2 C. CS 2 D. CaO E. MgI 2 Page 2
24. The electron dot formula for AsCl 3 shows: (complete) A. a total of 84 electron dots B. three single bonds and 10 lone pairs C. two single bonds, one double bond, and 9 lone pairs D. one single bond, two double bonds, and 8 lone pairs E. three single bonds and one lone pair 25. Which of the following is a useful guideline for the application of formal charges? For neutral molecules: A. a Lewis structure in which there are no formal charges is preferred. B. Lewis structures with large formal charges (+2,+3 and/or -2,-3) are preferred. C. the preferred Lewis structure is one in which positive formal charges are on the most electronegative atoms. 26. Which of the following pairs of elements would be most likely to form an ionic compound? A. Cl and I B. Al and K C. Cl and Mg D. C and S E. Al and Mg 27. Which molecule has a Lewis structure that does not obey the octet rule? A. N 2 O B. CS 2 C. PH 3 D. CCl 4 E. NO 2 28. Use bond energies to estimate the enthalpy change (ΔH) for the reaction CH 4 + Cl 2 CH 3 Cl + HCl BE(C H) = 1074 kj/mol BE(C Cl) = 499 kj/mol BE(H Cl) = 802 kj/mol BE(Cl Cl) = 1074 kj/mol A. -103 kj B. -109 kj C. +275 kj D. +109 kj E. +103 kj 29. The Lewis dot symbol for the Ca 2+ ion is A. Ca 2+ B. Ca C. Ca 2+ D. Ca2+ E. Ca 30. Which of the following solids would have the highest melting point? A. NaF B. NaCl C. NaBr D. NaI Page 3
32. Predict the geometry and polarity of the CS 2 molecule. A. linear, polar B. linear, nonpolar C. tetrahedral, nonpolar D. bent, nonpolar E. bent, polar 33. The F Cl F bond angles in ClF 3 are A. 90 only. B. 109.5 only. C. 120 only. D. 180 only. E. 90 and 180. 34. In which one of the following molecules is the central atom sp2 hybridized? A. SO 2 B. N 2 O C. BeCl 2 D. NF 3 E. PF 5 35. Which one of the following molecules has an atom with an incomplete octet? A. NF 3 B. H 2 O C. AsCl 3 D. GeH 4 E. BF 3 36. The hybridization of the phosphorus atom in the cation PH 2 + is: a) sp 2 b) sp 3 c) dsp d) sp e) none of these 37. In the molecule C 2 H 4 the valence orbitals of the carbon atoms are assumed to be a) not hybridized. b) sp hybridized. c) sp 2 hybridized. d) sp 3 hybridized. e) dsp hybridized. 38. Which of the following statements is (are) incorrect? I. The hybridization of boron in BF 3 is sp 2. II. The molecule XeF 4 is nonpolar. III. The bond order of N 2 is three. IV. The molecule HCN has two pi bonds and two sigma bonds. a) All four statements are correct. b) II is incorrect. c) I and IV are incorrect. d) II and III are incorrect. e) II, III, and IV are incorrect. Page 4
39. Atoms which are sp 2 hybridized form pi bond(s). a) 0 b) 1 c) 2 d) 3 e) 4 Page 5
40. The hybridization of the central atom in XeF 5 + is: a) sp b) sp 2 c) sp 3 d) dsp 3 e) d 2 sp 3 41. The hybridization of the central atom in ClF 2 + is: a) sp b) sp 2 c) sp 3 d) dsp 3 e) d 2 sp 3 42. The hybridization of the central atom in I 3 - is: a) sp b) sp 2 c) sp 3 d) dsp 3 e) d 2 sp 3 43. The hybridization of the central atom in O 3 is: a) sp b) sp 2 c) sp 3 d) dsp 3 e) d 2 sp 3 44. Which of the following molecules contains a central atom with sp 2 hybridization? a) b) c) Page 6
d) e) 45. What hybridization is predicted for the nitrogen atom in the NO 3 ion? a) sp 2 b) sp 3 c) sp 3 d d) sp 3 d 2 e) none of these Page 7
46. Which of the following does not contain at least one pi bond? a) H 2 CO b) CO 2 c) C 2 H 4 d) C 3 H 8 e) All of these (a-d) contain at least one pi bond. 47. Consider the following Lewis structure Which statement about the molecule is false? a) There are 10 sigma and 2 pi bonds. b) C 2 is sp 2 hybridized with bond angles of 120. c) Oxygen is sp 3 hybridized. d) This molecule contains 28 valence electrons. e) There are some H C H bond angles of about 109 in the molecule. Page 8
48. Consider the following Lewis structure: What is the hybridization of the oxygen atom and carbon atoms 1, 2, and 4, respectively? O C 1 C 2 C 4 Option 1: sp 3 sp 3 sp sp 2 Option 2: sp sp 3 sp sp Option 3: sp sp 2 sp sp 2 Option 4: sp 2 sp 3 sp 2 sp 3 Option 5: sp sp 3 sp 2 sp a) Option 1 b) Option 2 c) Option 3 d) Option 4 e) Option 5 49. The following statements concern molecules that require resonance. Which is true? a) The pi bonding is most clearly delocalized. b) The sigma bonding is most clearly delocalized. c) Both the sigma and pi bonding are delocalized. d) The benzene molecule is best described by the MO theory. e) The benzene molecule is best described by the localized electron model. 50. Consider the benzene molecule. Which of the following statements about the molecule is false? a) All six C C bonds are known to be equivalent. b) Each carbon atom is sp 2 hybridized. c) The localized electron model must invoke resonance to account for the six equal C C bonds. d) It has delocalized pi bonding in the molecule. e) The pi bonds of carbon involve sp 2 orbitals. Page 9
No. in Q-Bank No. on Test Correct Answer 9-33 1 C 10-32 2 C 9-20 3 A 9-66 4 D 9-63 5 B 9-50 6 C 9-28 7 C 9-25 8 C 10-18 9 E 10-6 10 D 10-7 11 D 9-59 12 C 9-37 13 B 9-44 14 D 9-31 15 E 10-29 16 B 9-23 17 D 9-47 18 D 9-56 19 B 10-9 20 E 10-5 21 A 10-23 22 C 9-5 23 C 9-43 24 B 9-51 25 A 9-4 26 C 9-64 27 E 9-69 28 A 9-14 29 D 9-18 30 A 9-22 31 E 10-24 32 B 10-16 33 E 10-30 34 A 9-62 35 E Answer Key for Test "ch 9 and 10 test.tst", 2/17/2010 36.ANS:a) sp 2 PAGE: 9.1 37ANS: c) sp 2 hybridized. PAGE: 9.1 38ANS: a) All four statements are correct. PAGE: 9.1 39ANS: b) 1 PAGE: 9.1 40ANS: e) d 2 sp 3 PAGE: 9.1 Page 10
41ANS: c) sp 3 PAGE: 9.1 42ANS:d) dsp 3 PAGE: 9.1 43ANS: e) sp 2 PAGE: 9.1 ANS: b) PAGE: 9.1 44 45ANS: a) sp 2 PAGE: 9.1 46ANS:d) C 3 H 8 PAGE: 9.1 47ANS: c) Oxygen is sp 3 hybridized. PAGE: 9.1 48ANS: a) Option 1 PAGE: 9.1 49ANS: a) The pi bonding is most clearly delocalized. PAGE: 9.5 50ANS: e) The pi bonds of carbon involve sp 2 orbitals. PAGE: 9.5 Page 11