Chemistry: A Molecular Approach, 2e (Tro)Chapter 9 Chemical Bonding I: Lewis Theory

Multiple Choice Questions

6) Which of the following represent the Lewis structure for N?A) B) C) D) E) Answer: ADiff: 1 Page Ref: 9.3

7) Which of the following represent the Lewis structure for Cl?A) B) C) D) E) Answer: BDiff: 1 Page Ref: 9.3

8) Which of the following represent the Lewis structure for Mg?A) B) C)

D) E) Answer: CDiff: 1 Page Ref: 9.3

9) Which of the following represent the Lewis structure for Br⁻?A) B) C) D) E) Answer: DDiff: 1 Page Ref: 9.4

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10) Which of the following represent the Lewis structure for Ca2⁺?A) B) C) D) E) Answer: EDiff: 1 Page Ref: 9.4

11) Which of the following represent the Lewis structure for S2⁻?A) B) C) D) E) Answer: ADiff: 1 Page Ref: 9.4

14) Use Lewis theory to determine the chemical formula for the compound formed between Ca and N.A) CaNB) Ca3N2C) CaN2D) Ca2NE) Ca2N3Answer: BDiff: 2 Page Ref: 9.4

15) Use Lewis theory to determine the chemical formula for the compound formed between Rb and S.A) RbSB) RbS2C) Rb2SD) Rb2S3E) Rb3S2Answer: CDiff: 2 Page Ref: 9.4

16) Use Lewis theory to determine the chemical formula for the compound formed between Mg and Br.A) MgBrB) Mg2Br3C) Mg3Br2D) MgBr2

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E) Mg2BrAnswer: DDiff: 2 Page Ref: 9.4

17) Use Lewis theory to determine the chemical formula for the compound formed between Al and O.A) Al3O2B) Al2O3C) AlO2D) Al2OE) AlOAnswer: BDiff: 2 Page Ref: 9.4

18) Use Lewis theory to determine the chemical formula for the compound formed between Ca and N.A) Ca3N2B) Ca2N3C) CaN2D) CaNAnswer: ADiff: 2 Page Ref: 9.4

19) Use Lewis theory to determine the chemical formula for the compound formed between K and I.A) KI2B) K2IC) KID) K2I2Answer: CDiff: 2 Page Ref: 9.4

23) Identify the compound with the highest magnitude of lattice energy.A) NaClB) KClC) LiClD) CsClAnswer: CDiff: 2 Page Ref: 9.4

24) Identify the compound with the lowest magnitude of lattice energy.A) KClB) KBrC) SrOD) CaOAnswer: B

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Diff: 2 Page Ref: 9.4

25) Place the following in order of decreasing magnitude of lattice energy.

K2O Rb2S Li2O

A) Li2O > K2O > Rb2SB) Li2O > Rb2S > K2OC) Rb2S > K2O > Li2OD) Rb2S > Li2O > K2OE) K2O > Li2O > Rb2SAnswer: ADiff: 2 Page Ref: 9.4

26) Place the following in order of decreasing magnitude of lattice energy.

NaF RbBr KCl

A) RbBr > NaF > KClB) NaF > KCl > RbBrC) KCl > NaF > RbBrD) NaF > RbBr > KClE) RbBr > KCl > NaFAnswer: BDiff: 2 Page Ref: 9.4

27) Place the following in order of increasing magnitude of lattice energy.

CaO MgO SrS

A) MgO < CaO < SrSB) SrS < MgO < CaOC) SrS < CaO < MgOD) CaO < MgO < SrSE) CaO < SrS < MgOAnswer: CDiff: 2 Page Ref: 9.4

28) Place the following in order of increasing magnitude of lattice energy.

MgO LiI CaS

A) CaS < MgO < LiIB) LiI < CaS < MgOC) MgO < CaS < LiID) LiI < MgO < CaSE) MgO < LiI < CaSAnswer: B

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Diff: 2 Page Ref: 9.4

29) Place the following in order of decreasing magnitude of lattice energy.

KF MgS RbI

A) RbI > KF > MgSB) RbI > MgS > KFC) MgS > RbI > KFD) KF > RbI > MgSE) MgS > KF > RbIAnswer: EDiff: 2 Page Ref: 9.4

44) Identify the shortest bond.A) single covalent bondB) double covalent bondC) triple covalent bondD) all of the above bonds are the same lengthAnswer: CDiff: 1 Page Ref: 9.5

45) Identify the weakest bond.A) single covalent bondB) double covalent bondC) triple covalent bondD) all of the above bonds are the same strengthAnswer: ADiff: 1 Page Ref: 9.5

46) Identify the number of bonding pairs and lone pairs of electrons in water.A) 1 bonding pair and 1 lone pairB) 1 bonding pair and 2 lone pairsC) 2 bonding pairs and 2 lone pairsD) 2 bonding pairs and 1 lone pairE) 3 bonding pairs and 2 lone pairsAnswer: CDiff: 1 Page Ref: 9.5

60) Choose the best Lewis structure for BeF2.

A) B) C) D) E) Answer: D

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Diff: 2 Page Ref: 9.7

61) Choose the best Lewis structure for OCl2.

A) B) C) D) E) Answer: EDiff: 2 Page Ref: 9.7

62) Choose the best Lewis structure for CH2Cl2.A)

B)

C)

D)

E)

Answer: BDiff: 2 Page Ref: 9.7

63) Give the number of valence electrons for XeI2.A) 22B) 20C) 18D) 24Answer: ADiff: 2 Page Ref: 9.7

64) Choose the best Lewis structure for XeI2.

A) B) C)

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D) E) Answer: CDiff: 2 Page Ref: 9.7

65) Give the number of valence electrons for ICl5.A) 36B) 40C) 42D) 44E) 46Answer: CDiff: 2 Page Ref: 9.7

66) Choose the best Lewis structure for ICl5.A)

B)

C)

D)

E)

Answer: DDiff: 2 Page Ref: 9.7

67) Give the number of valence electrons for SF4.A) 28B) 30C) 32

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D) 34Answer: DDiff: 2 Page Ref: 9.7

68) Choose the best Lewis structure for SF4.A)

B)

C)

D)

E)

Answer: EDiff: 2 Page Ref: 9.7

69) Give the number of pairs of valence electrons for BF3.A) 16B) 8C) 14D) 10E) 12Answer: EDiff: 2 Page Ref: 9.7

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70) Choose the best Lewis structure for BF3.A)

B)

C)

D)

E)

Answer: BDiff: 2 Page Ref: 9.7

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71) Choose the best Lewis structure for NO3⁻.A)

B)

C)

D)

E)

Answer: ADiff: 2 Page Ref: 9.7

72) Give the number of valence electrons for SO42-.A) 32B) 30C) 34D) 28E) 36Answer: ADiff: 2 Page Ref: 9.7

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73) Choose the best Lewis structure for SO42⁻.A)

B)

C)

D)

E)

Answer: ADiff: 2 Page Ref: 9.7

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74) Choose the best Lewis structure for PO43⁻.A)

B)

C)

D)

E)

Answer: CDiff: 2 Page Ref: 9.7

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75) Choose the best Lewis structure for SeO42⁻.A)

B)

C)

D)

E)

Answer: DDiff: 2 Page Ref: 9.7

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76) Choose the best Lewis structure for NH4⁺.A)

B)

C)

D)

E)

Answer: EDiff: 2 Page Ref: 9.7

80) Using Lewis structures and formal charge, which of the following ions is most stable?

OCN⁻ ONC⁻ NOC⁻

A) OCN⁻B) ONC⁻C) NOC⁻D) None of these ions are stable according to Lewis theory.E) All of these compounds are equally stable according to Lewis theory.Answer: ADiff: 2 Page Ref: 9.8

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81) Draw the Lewis structure for SO42⁻. How many equivalent resonance structures can be drawn?A) 6B) 2C) 4D) 3E) 8Answer: ADiff: 3 Page Ref: 9.8

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82) Draw the best Lewis structure for Cl3⁻. What is the formal charge on the central Cl atom?A) -1B) 0C) +1D) +2E) -2Answer: ADiff: 3 Page Ref: 9.8

83) Draw the best Lewis structure for the free radical, NO2. What is the formal charge on the N?A) 0B) +1C) -1D) +2E) -2Answer: BDiff: 3 Page Ref: 9.8

84) Draw the best Lewis structure for CH3-1. What is the formal charge on the C?A) 0B) 1C) -1D) 2Answer: CDiff: 3 Page Ref: 9.8

85) Draw the best Lewis structure for CH3+1. What is the formal charge on the C?A) 0B) 1C) -1D) 2Answer: BDiff: 3 Page Ref: 9.8

86) Draw the best Lewis structure for BrO4⁻ and determine the formal charge on bromine.A) -1B) +1C) 0D) +2E) +3Answer: CDiff: 3 Page Ref: 9.8

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87) Which of the following elements can form compounds with an expanded octet?A) SeB) CC) LiD) FE) All of the above elements can form compounds with an expanded octet.Answer: ADiff: 1 Page Ref: 9.9

88) Which of the following elements can form compounds with an expanded octet?A) NB) BrC) FD) BeE) None of the above can form compounds with an expanded octet.Answer: BDiff: 1 Page Ref: 9.9

91) Choose the bond below that is the strongest.A) C-FB) C=OC) C-ID) I-IE) C≡NAnswer: EDiff: 1 Page Ref: 9.10

92) Choose the bond below that is the strongest.A) N=OB) N-IC) N-OD) N-SE) N=NAnswer: ADiff: 1 Page Ref: 9.10

95) Which compound has the longest carbon-carbon bond length?A) CH3CH3B) CH2CH2C) HCCHD) all bond lengths are the sameAnswer: ADiff: 1 Page Ref: 9.10

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97) Place the following in order of increasing bond length.

C-F C-S C-Cl

A) C-S < C-Cl < C-FB) C-Cl < C-F < C-SC) C-F < C-S < C-ClD) C-F < C-Cl < C-SE) C-S < C-F < C-Cl Answer: DDiff: 1 Page Ref: 9.10

98) Place the following in order of decreasing bond length.

H-F H-I H-Br

A) H-F > H-Br > H-IB) H-I > H-F > H-BrC) H-I > H-Br > H-FD) H-Br > H-F > H-IE) H-F > H-I > H-BrAnswer: CDiff: 1 Page Ref: 9.10

100) Place the following in order of increasing bond length.

NO2⁻ NO3⁻ NO

A) NO < NO2⁻ < NO3⁻B) NO2⁻ < NO3⁻ < NOC) NO3⁻ < NO < NO2⁻D) NO < NO3⁻ < NO2⁻E) NO3⁻ < NO2⁻ < NOAnswer: DDiff: 1 Page Ref: 9.10

101) Rank the following molecules in decreasing bond energy.

Cl2 Br2 F2 I2A) I2 > Br2 > Cl2 > F2B) Cl2 > Br2 > F2 > I2C) I2 > Cl2 > Br2 > F2D) Cl2 > I2 > F2 > Br2Answer: BDiff: 2 Page Ref: 9.10

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102) Which of the following processes are exothermic?A) Cl2(g) → 2Cl(g)B) Br(g) + e⁻ → Br⁻(g)C) Li(s) → Li(g)D) NaF(s) → Na⁺(g) + F⁻(g)E) None of the above are exothermic.Answer: BDiff: 2 Page Ref: 9.10

103) Which of the following processes are exothermic?A) the second ionization energy of MgB) the sublimation of LiC) the breaking the bond of I2D) the formation of NaBr from its constituent elements in their standard stateE) None of the above are exothermicAnswer: DDiff: 2 Page Ref: 9.10

104) Which of the following processes are endothermic?A) K⁺(g) + I⁻(g) → KI(s)B) 2 Br(g) → Br2(g)C) Ca(s) → Ca(g)

D) 2 Na(s) + O2(g) → Na2O(s)E) None of the above are endothermic.Answer: CDiff: 2 Page Ref: 9.10

105) Which of the following processes are endothermic?A) the reaction associated with the lattice energy of LiCl.B) the reaction associated with the ionization energy of potassium.C) the reaction associated with the heat of formation of CaS.D) the formation of F2 from its elements in their standard states.E) None of the above are endothermic.Answer: BDiff: 2 Page Ref: 9.10

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106) Use the bond energies provided to estimate ΔH°rxn for the reaction below.

PCl3(g) + Cl2(g) → PCl5(l) ΔH°rxn = ?Bond Bond Energy (kJ/mol)Cl-Cl 243P-Cl 331

A) -243 kJB) -419 kJC) -662 kJD) -67 kJE) -905 kJAnswer: BDiff: 3 Page Ref: 9.10

107) Use the bond energies provided to estimate ΔH°rxn for the reaction below.

2 Br2(l) + C2H2(g) → C2H2Br4(l) ΔH°rxn = ?Bond Bond Energy (kJ/mol)Br-Br 193C≡C 837C-C 347C-Br 276C-H 414

A) +407 kJB) -324 kJC) -228 kJD) +573 kJE) -648 kJAnswer: CDiff: 3 Page Ref: 9.10

108) Use the bond energies provided to estimate ΔH°rxn for the reaction below.

CH3OH(l) + 2 O2(g) → CO2(g) + 2 H2O(g) ΔH°rxn = ?Bond Bond Energy (kJ/mol)C-H 414C-O 360C=O 799O=O 498O-H 464

A) +473 kJB) -91 kJC) -486 kJD) -392 kJE) +206 kJ

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Answer: DDiff: 3 Page Ref: 9.10

109) Use the bond energies provided to estimate ΔH°rxn for the reaction below.

XeF2 + 2 F2 → XeF6 ΔH°rxn = ?Bond Bond Energy (kJ/mol)Xe-F 147F-F 159

A) -429 kJB) +159 kJC) -660 kJD) +176 kJE) -270 kJAnswer: EDiff: 3 Page Ref: 9.10

110) Use the bond energies provided to estimate ΔH°rxn for the reaction below.

C2H4(g) + H2(g) → C2H6(g) ΔH°rxn = ?Bond Bond Energy (kJ/mol)C-C 347C-H 414C=C 611C≡C 837H-H 436

A) -128 kJB) +98 kJC) +700 kJD) -102 kJE) -166 kJAnswer: ADiff: 3 Page Ref: 9.10

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