1. Chemistry 107
Exam 7-9 Good Luck!

2. 1. Determine the wavelength (in nm) of an X-ray with a frequency of 4
1. Determine the wavelength (in nm) of an X-ray with a frequency of 4.2 x 1018 Hz.
7.1 x 10–11
7.1 x 10–2
1.3 x 1027
1.4 x 1010
7.1 x 10–18
Answer: b
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3. 2. A major league pitcher throws a 148. 8 g baseball at a speed of 92
2. A major league pitcher throws a g baseball at a speed of 92.5 mph (41.4 m/s). What is the de Broglie wavelength of the baseball in meters?
4.81 x 10–38
4.81 x 10– 41
1.08 x 10– 34
1.08 x 10– 37
1.08 x 10– 40
Answer: c
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4. 3. An electron in a hydrogen atom in the n = 6 energy level emits 109
3. An electron in a hydrogen atom in the n = 6 energy level emits kJ/ mol of energy in a transition to a lower energy level. To what energy level does the electron fall? 1 2 3 4 5
Answer: c
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5. 4. Which of the following transitions for an electron in a hydrogen atom would release the largest quantum of energy?
n = 3 → n = 1
n = 4 → n = 3
n = 1 → n = 4
n = 2 → n = 1
Answer: a
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6. 5. Which of the following is NOT an allowed set of quantum numbers?
n = 4 l = 3 ml = 3
n = 1 l = 0 ml = 0
n = 5 l = 4 ml = – 2
n = 2 l = 1 ml = 0
n = 3 l = 3 ml = – 2
Answer: e
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7. 6. What is the frequency (Hz) of a infrared light that emits 24
6. What is the frequency (Hz) of a infrared light that emits 24.5 kJ/ mol of energy?
3.70x1034
6.14x1013
4.92x1019
8.17x10–8
2.70x10–35
Answer: b
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8. 7. Ultraviolet light emits a total of 2
7. Ultraviolet light emits a total of 2.5x10–17 J of light at a wavelength of 9.8x10–7 m. How many photons does this correspond to? 1 10 25
100
125
Answer: e
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9. 8. Determine the wavelength (nm) of light absorbed when an electron in a hydrogen atom transitions from the n = 3 to the n = 5 energy level.
434 nm
656 nm
684 nm
780 nm
1280 nm
Answer: e
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10. 9. The de Broglie wavelength of a 455 kg car is found to be 5
9. The de Broglie wavelength of a 455 kg car is found to be 5.43x10–38 nm. Calculate the speed (m/ s) of the car.
26.8 m/ s
37.3 m/ s
2.68x10–8 m/ s
3.73x107 m/ s
3.00x108 m/ s
Answer: a
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11. 10. Which orbital is described by the following set of quantum numbers
10. Which orbital is described by the following set of quantum numbers? n = 3 l = 1 ml = –1 1s 2s 3s 3p 3d
Answer: c
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12. 11. What is the ground state electron configuration for Mo?
Mo: [Kr]5s24d4
Mo: [Kr]5s04d6
Mo: [Ar]4s23d4
Mo: [Ar]4s13d5
Mo: [Kr]5s14d5
Answer: e
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13. 12. Which of the following correctly illustrates the valence electron configuration of sulfur?b) c)
Answer: a d)
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14. a) Ge b) Te c) Sn d) Se e) Sb
13. Which element’s 4+ ion would have the following electron configuration?
[Kr]4d10
a) Ge b) Te c) Sn d) Se e) Sb
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15. 14. Consider the following isoelectronic series: Cl– Ar K+ Ca2+
Which particle is the largest?
a) Cl–
b) Ar
c) K+
d) Ca2+
e) All particles are the same size.
Answer: a
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16. 15. Consider the following successive ionization energies (kJ/mol):
IE IE IE IE IE IE IE7
, ,345
Which element in period three would most likely show this trend in ionization energies?
a) Mg
b) Al
c) Si
d) P
e)S
Answer: d
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17. 16. What is the ground state electron configuration for V?
V: [Kr]4s33d2
V: [Kr]4s24d3
V: [Ar]4s23d3
V: [Ar]3d3
Answer: c
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18. a) Rb b) Sr c) Cs d) Ba e) Cl
17. Which element is the largest?
a) Rb b) Sr c) Cs d) Ba e) Cl
Answer: c
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19. a) Sn b) Sn2+ c) Sn4+ d) Sn2+ and Sn4+ e) All are paramagnetic
18. Which of the following is diamagnetic?
a) Sn b) Sn2+ c) Sn4+ d) Sn2+ and Sn4+ e) All are paramagnetic
Answer: d
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20. 19. Which element is the most non-metallic?
a) K b) Ca c) Mg d) O e) F
Answer: e
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21. 20. How many valence electrons does an atom of Sulfur possess?
a. 2 b. 3 c. 4 d. 5 e. 6
Answer: e
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22. 21. Which element has the greatest effective nuclear charge?
a. O b. F c. S d. Cl e. P
Answer: b
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23. 22. Which of the following sets gives the correct formal charges for the elements in the Lewis structure below?
S: –2 C: – N: –3
S: +6 C: N: +5
S: –2 C: N: –3
S: +1 C: N: –1
S: 0 C: N: –1
Answer: e
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24. 23. Rank the following in order of increasing bond polarity: H─F
23. Rank the following in order of increasing bond polarity: H─F H─Br F─F Na─Cl
H─F < H─Br < F─F < Na─Cl
F─F < H─F < H─Br < Na─Cl
H─Br < H─F < F─F < Na─Cl
F─F < H─Br < H─F < Na─Cl
Na─Cl < H─F < H─Br < F─F
Answer: d
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25. 24. Determine the formal charge of chlorine in the most stable Lewis structure for ClO2–.–2 –1 +1 +2
Answer: c
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26. 25. Which of the following compounds has ionic bonding?
NO2 Al
CaCO3
Answer: e
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27. 26. Use average bond energies to determine ΔHrxn for the burning of H2
26. Use average bond energies to determine ΔHrxn for the burning of H2. H2(g) + ½ O2(g) → H2O(g)
6 kJ
470 kJ
–243 kJ
–350 kJ
–421 kJ
Bond
Bond Energy (kJ/mol)
H─H
436
O═O
498
O─O
142
O─H
464
Answer: c
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28. 27. Estimate the enthalpy change for the combustion of methanol, using bond energies.
-3454 kJ
2652 kJ
-1426 kJ
126 kJ
-802 kJ
Answer: e
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29. 28. Draw the Lewis structure for NO3–
28. Draw the Lewis structure for NO3– . How many equivalent resonance structures can be drawn? 1 2 3 4 5
Answer: c
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30. 29. Draw the best Lewis structure for Ca(OH)2
29. Draw the best Lewis structure for Ca(OH)2. How many lone pairs of electrons are on Ca? 1 2 3 4
Answer: d
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31. The Answers 1. B 2. C 3. C 4. A 5. E 6. B 7. E 8. E 9. A 10. D 11. E