Ch 12 Practice Problems

1. T F True or False? In general, Z is less than Zeff.

2. Which of the following frequencies corresponds to light with the longest wavelength?A) 3.00 1013 s–1

B) 4.12 105 s–1

C) 8.50 1020 s–1

D) 9.12 1012 s–1

E) 3.20 109 s–1

3. Which form of electromagnetic radiation has the shortest wavelengths?A) gamma raysB) microwavesC) radio wavesD) infrared radiationE) X rays

Use the following to answer question 4:

A photographic film needs a minimum of 80.0 kJ/mol for exposure.

4. The frequencies of visible light are in the range 7.5 × 1014 Hz to 4.3 × 1014 Hz. Is the radiation visible to the human eye?A) yesB) noC) More information is needed.

5. From the following list of observations, choose the one that most clearly supports the conclusion that electrons have wave properties.A) the emission spectrum of hydrogenB) the photoelectric effectC) the scattering of alpha particles by metal foilD) diffractionE) cathode "rays"

6. From the following list of observations, choose the one that most clearly supports the conclusion that electromagnetic radiation has wave characteristics.A) the emission spectrum of hydrogenB) the photoelectric effectC) the scattering of alpha particles by metal foilD) diffractionE) cathode "rays"

7. From the following list of observations, choose the one that most clearly supports the conclusion of de Broglie wavelengths.A) the emission spectrum of hydrogenB) the photoelectric effectC) the scattering of alpha particles by metal foilD) diffractionE) cathode "rays"

8. From the following list of observations, choose the one that most clearly supports the conclusion that the mass of the atom is located mainly in the nucleus.A) the emission spectrum of hydrogenB) the photoelectric effectC) the scattering of alpha particles by metal foilD) diffractionE) cathode "rays"

9. From the following list of observations, choose the one that most clearly supports the conclusion that atoms contain electrons.A) the emission spectrum of hydrogenB) the photoelectric effectC) the scattering of alpha particles by metal foilD) diffractionE) cathode “rays”

Use the following to answer question 10:

A photographic film needs a minimum of 80.0 kJ/mol for exposure.

10. What is the longest wavelength of radiation with sufficient energy to expose the film?A) 1.50 × 10–3 mB) 1.50 × 10–6 mC) 1.50 × 10–9 mD) 1.50 × 10–12 mE) none of these

11. Light has a wavelength of 6.0 102 nm. What is the energy of a photon of this light?A) 1.10 10–19 JB) 3.31 10–19 JC) 2.71 1018 JD) 3.68 10–20 JE) 1.33 10–18 J

12. What is the wavelength, in nanometers, of a photon of light whose frequency is 5.86 1014 Hz?A) 1.95 102 nmB) 5.12 102 nmC) 3.39 102 nmD) 2.95 102 nmE) 1.29 10-7 nm

13. Consider an atom traveling at 1% of the speed of light. The de Broglie wavelength is found to be 3.31 10–3 pm. Which element is this?A) HeB) CaC) FD) BeE) P

14. From the following list of observations, choose the one that most clearly supports the conclusion that electrons in atoms have quantized energies.A) the emission spectrum of hydrogenB) the photoelectric effectC) the scattering of alpha particles by metal foilD) diffractionE) cathode "rays"

15. Which of the following statements is(are) true?I. An excited atom can return to its ground state by absorbing electromagnetic radiation.

II. The energy of an atom is increased when electromagnetic radiation is emitted from it.

III. The energy of electromagnetic radiation increases as its frequency increases.

IV. An electron in the n = 4 state in the hydrogen atom can go to the n = 2 state by emitting electromagnetic radiation at the appropriate frequency.

V. The frequency and wavelength of electromagnetic radiation are inversely proportional to each other.

A)II, III, IVB) III, VC) I, II, IIID)III, IV, VE) I, II, IV

16. In an investigation of the electronic absorption spectrum of a particular element, it is found that a photon having = 500 nm provides just enough energy to promote an electron from the second quantum level to the third. From this information, we can deduceA)the energy of the n = 2 level.B) the energy of the n = 3 level.C) the sum of the energies of the n = 2 and n = 3 levels.D)the difference between the energies of the n = 2 and n = 3 levels.E) all of these.

17. What is the wavelength of light that is emitted when an excited electron in the hydrogen atom falls from the n = 5 level to the n = 2 level?A) 5.12 × 10-7 mB) 4.34 × 10-7 mC) 6.50 × 10-7 mD) 5.82 × 10-7 mE) none of these

18. Which of the following is a reasonable criticism of the Bohr model of the atom?A) It makes no attempt to explain why the negative electron does not eventually fall into the positive nucleus.B) It does not adequately predict the line spectrum of hydrogen.C) It does not adequately predict the ionization energy of the valence electron(s) for elements other than hydrogen.D) It does not adequately predict the ionization energy of the first-energy-level electrons for elements other than hydrogen.E) It shows the electrons to exist outside of the nucleus.

19. In Bohr's atomic theory, when an electron moves from one energy level to another energy level more distant from the nucleus,A) energy is emitted.B) energy is absorbed.C) no change in energy occurs.D) light is emitted.E) none of these

20. For which of the following transitions does the light emitted have the longest wavelength?A) n = 4 to n = 3B) n = 4 to n = 2C) n = 4 to n = 1D) n = 3 to n = 2E) n = 2 to n = 1

21. In the hydrogen spectrum, what is the wavelength of light associated with the n = 2 to n = 1 electron transition?A) 1.097 nmB) 364.9 nmC) 0.1097 10–8 cmD) 9.122 10–8 mE) 1.216 10–7 m

22. On a planet where the temperature is so high, the ground state of an electron in the hydrogen atom is n = 4. What is the ratio of IE on this planet to that on earth?A) 1:4B) 4:1C) 1:16D) 16:1E) 1:1

23. The ionization energy for a hydrogen atom is 1.31 × 106 J/mol. What is the ionization energy for He+?A) 8.72 × 10-18 J/molB) 1.31 × 106 J/molC) 5.25 × 106 J/molD) 2.18 × 10-18 J/molE) 2.63 × 106 J/mol

24. The wavelength of light associated with the n = 2 to n = 1 electron transition in the hydrogen spectrum is 1.216 10–7 m. By what coefficient should this wavelength be multiplied to obtain the wavelength associated with the same electron transition in the Li2+ ion?A) 1/9B) 1/7C) 1/4D) 1/3E) 1

25. The energy expressions for the electrons in the He+ ion and the hydrogen atom are En (H) = -a/n2 and En (He+) = -4a/n2

Which of the following statements is(are) correct?

I. For the transitions n1 n2 , the frequency is larger for H than for He+.

II. The first ionization energy of the H atom is smaller than the second ionization energy of the He atom.

III. The 1s orbital in He+ is larger (in the sense that the probability density is shifted outward) than the 1s orbital in H.

A) I onlyB) II onlyC) III onlyD) I and II onlyE) I, II, and III

26. What is the probability of finding a particle in a one-dimensional box in energy level n = 4 between x = L/4 and x = L/2? (L is the length of the box.)A) 12.5%B) 25%C) 33%D) 37.5%E) 50%

27. For an electron in a one-dimensional box, what is the minimum energy to excite the electron from the ground state?

A)

B)

C)

D)

E)

28. The energy equation for a particle in a cubic box of dimensions Lx = Ly = Lz is

For a particle in a cubic box, how many degenerate energy levels have energy equal to 14 h2/8 mL2?

A) 1B) 3C) 6D) 8E) 12

29. For an electron in a 2.00-nm one-dimensional box, calculate the wavelength of electromagnetic radiation to excite the electron from the ground state to the level with n = 3.A) 1650 nmB) 13,200 nmC) 1470 nmD) 12,100 nmE) none of these

30. An electron in a one-dimensional box requires energy with wavelength 8080 nm to excite it from the n = 2 energy level to the n = 3 energy level. Calculate the length of the box.A) 1.00 nmB) 1.50 nmC) 2.50 nmD) 3.00 nmE) 3.50 nm

31. An electron in a 10.0-nm one-dimensional box is excited from the ground state into a higher energy state by absorbing a photon with wavelength 1.374 ×10-5 m. Determine the final energy level for this transition.A) n = 2B) n = 3C) n = 4D) n = 5E) n = 6

32. Which of the following statements about quantum theory is incorrect?A) The energy and position of an electron cannot be determined simultaneously.B) Lower energy orbitals are filled with electrons before higher energy orbitals.C) When filling orbitals of equal energy, two electrons will occupy the same orbital before filling a new orbital.D) No two electrons can have the same four quantum numbers.E) All of these are correct.

33. Which of the following is not determined by the principal quantum number, n, of the electron in a hydrogen atom?A) the energy of the electronB) the minimum wavelength of the light needed to remove the electron from the atom.C) the size of the corresponding atomic orbital(s)D) the shape of the corresponding atomic orbital(s)E) All of the above are determined by n.

34. Which of the following statements is true?A) We can determine the exact location of an electron if we know its energy.B) An electron in a 2s orbital can have the same n, l, and ml quantum numbers as an electron in a 3s orbital.C) Ni has 2 unpaired electrons in its 3d orbitals.D) In the building up of atoms, electrons occupy the 4f orbitals before the 6s orbitals.E) Only three quantum numbers are needed to uniquely describe an electron.

35. How many electrons in an atom can have the quantum numbers n = 3, l = 1?A) 10B) 2C) 6D) 18E) 32

36. How many electrons can be described by the quantum numbers n = 3, l = 3, ml = -1?A) 0B) 2C) 6D) 10E) 14

37. The number of orbitals having a given value of l is equal toA) 2l + 1B) 2n + 2C) 3lD) l + ml

E) the number of lobes in each orbital

38. Which of the following combinations of quantum numbers is not allowed?(Combinations are listedas follows: n, l, m(l), m(s).)

A)1 1 0 -1/2B) 3 0 0 -1/2C) 3 1 1 ½D)5 3 1 -1/2E) 3 2 0 1/2

39. How many electrons can be described by the quantum numbers n = 3, l = 1?A) 1B) 2C) 3D) 5E) 6

40. How many electrons can be described by the quantum numbers n = 4, l = 3, ml = 0?A) 0B) 2C) 6D) 10E) 14

41. How many f orbitals have the value n = 3?A) 0B) 3C) 5D) 7E) 1

42. Which of the following combinations of quantum numbers do not represent permissible solutions of the Schrodinger equation for the electron in the hydrogen atom? (In other words, which combination of quantum numbers is not allowed?) (Combinations are listed as follows: n, l, m(l), m(s).)A) 9 8 –4 1/2B) 8 2 2 1/2C) 6 –5 –1 1/2D) 6 5 –5 1/2E) All are allowed.

43. In which orbital does an electron experience the highest Zeff?A) Na (3s)B) Mg (3s)C) Al (3p)D) P (3p)E) S (3p)

44. What value is the closest estimate of Zeff for a valence electron of the calcium atom?A) 1B) 2C) 6D) 20E) 40

45. Which of the following statements is false?A) An orbital can accommodate at most two electrons.B) The electron density at a point is proportional to 2 at that point.C) The spin quantum number of an electron must be either +1/2 or –1/2.D) A 2p orbital is more penetrating than a 2s; that is, it has a higher electron density near the nucleus and inside the charge

cloud of a 1s orbital.E) In the usual order of filling, the 6s orbital is filled before the 4f orbital.

46. The first ionization energy of Mg is 735 kJ/mol. Calculate Zeff.A) 2.00B) 2.25C) 4.00D) 5.04E) none of these

47. How many electrons can be described by the quantum number n = 4?A) 8B) 10C) 2D) 18E) 32

48. How many electrons can be described by the quantum numbers n = 6, l = 2, ml = 0, ms = 1?A) 0B) 2C) 6D) 10E) 14

49. Which of the following atoms or ions has 3 unpaired electrons?A) CoB) OC) CaD) Br–

E) Zn2+

50. What is the electron configuration for the barium atom?A) 1s22s22p63s23p63d104s2

B) [Xe] 6s2

C) 1s22s22p63s23p64s1

D) 1s22s22p63s23p64s2

E) none of these

51. In which groups do all the elements have the same number of valence electrons?A) P, O, ClB) Ag, Cd, ArC) Na, Ca, BaD) P, As, SeE) N, P, As

52. What is the electron configuration of Cr3+?A) [Ar] 4s23d1

B) [Ar] 4s13d2

C) [Ar] 3d3

D) [Ar] 4s23d4

E) none of these

53. An element E has the electron configuration [Kr]4d105s25p3. What is the formula for the fluoride of E most likely to be?A) EF2

B) EF3

C) EFD) EF6

E) EF8

54. An element with the electron configuration [Xe]4f145d76s2 would belong to which class on the periodic table?A) transition elementsB) alkaline earth elementsC) halogensD) rare earth elementsE) none of these

55. What is the electron configuration of the element with atomic number 113?A) [Rn] 7s27f147d107p1

B) [Rn] 7s25f147d107p1

C) [Rn] 7s26d107p1

D) [Rn] 7s25f146d107p1

E) none of these

56. How many electrons can be contained in all of the orbitals with n = 4?A) 2B) 8C) 10D) 18E) 32

57. Which orbital has the highest energy in the rubidium atom?A) 1sB) 5s

C) 4sD) 4pE) 4d

58. Of the following elements, which has occupied d orbitals in its ground-state neutral atoms?A) BaB) NaC) AlD) PE) F

59. Of the following elements, which needs 3 electrons to complete its valence shell?A) BaB) KC) SiD) PE) Cl

60. Which is the highest occupied energy orbital in a silicon atom?A) 1sB) 2sC) 3sD) 3pE) 3d

61. Which of the following electron configurations is correct?A) Ga: [Kr]3d104s24p1

B) Mo: [Kr]5s24d5

C) Ca: [Ar]4s13d10

D) Br: [Kr]3d104s24p7

E) Bi: [Xe]6s24f145d106p3

62. Which atom has three 2p electrons in its ground state?A) SiB) AsC) ND) PE) none of these

63. What is the total number of electrons that can be accommodated in the level corresponding to n = 5?A) 2B) 8C) 18D) 32E) 50

64. How many unpaired electrons does chlorine have in its ground state?A) 1B) 2C) 3D) 17E) none of these

65. What is the electron configuration of Ti2+?A) [Ar] 4s2

B) [Ar] 4s13d1

C) [Ar] 3d2

D) [Ar] 4s23d2

E) none of these

66. How many unpaired electrons does arsenic have in its ground state?A) 1B) 2C) 3D) 33E) none of these

67. What is the electron configuration of Co3+?A) [Ar] 3d4

B) [Ar] 3d6

C) [Ar] 4s23d4

D) [Ar] 4s24d4

E) none of these

68. Which of the following atoms has 3 electrons in p orbitals in its valence shell?A) BaB) GaC) VD) BiE) none of these

69. What is the electron configuration for Cr2+?A) [Ar] 4s23d4

B) [Ar] 4s13d5

C) [Ar] 3d4

D) [Ar] 4s23d2

E) none of these

70. The number of unpaired electrons in the outer subshell of a Cl atom isA) 0.B) 1.C) 2.D) 3.E) none of these

71. For which element are the d orbitals completely filled in the neutral atom?A) potassiumB) vanadiumC) phosphorusD) ironE) bromine

72. For which of the following elements does the electron configuration for the lowest energy state show a partially filled d orbital?A) VB) KC) CuD) GaE) Ar

73. How many valence electrons do the alkaline earth metals have?A) 1B) 2C) 3D) 7E) 8

74. What is the electron configuration of indium?A) 1s22s22p63s23p63d104s24p64d105s25p15d10

B) 1s22s22p63s23p63d104s24d104p1

C) 1s23s22p63s23p64s24p64d105s25d105p1

D) 1s22s22p63s23p63d104s24p64d105s25p1

E) none of these

75. What is the electron configuration for the chromium atom?A) [Ar] 4s23d4

B) [Ar] 4s13d5

C) [Kr] 4s13d5

D) [Kr] 4s23d4

E) none of these

76. An element has the electron configuration [Kr] 4d105s25p2. The element is a(n)A) nonmetal.B) transition element.

C) metal.D) lanthanide.E) actinide.

77. How many of the following electron configurations for the species in their ground state are correct?

Ca 1s22s22p63s23p64s2

Mg 1s22s22p63s1

V [Ar] 3s23d3

As [Ar] 4s23d104p3

P 1s22s22p63p5

A) 1B) 2C) 3D) 4E) 5

78. What is the valence electron configuration of S?A) 3s23p4

B) 1s22s22p63s23p4

C) 4s24p4

D) 1s22s22p4

E) none of these

79. An atom of fluorine contains 9 electrons. How many of these electrons are in s orbitals?A) 2B) 4C) 6D) 8E) 10

80. How many unpaired electrons are there in an atom of sulfur in its ground state?A) 0B) 1C) 2D) 3E) 4

81. How many unpaired electrons does cobalt have in its ground state?A) 1B) 3C) 5D) 27E) 7

82. The valence electron configuration of an element is ns2(n – 1)d10np2. To which group does X belong?A) Group 3AB) Group 4AC) Group 5AD) Group 6AE) Group 7A

83. Place the elements C, N, and O in order of increasing ionization energy.A) C, N, OB) O, N, CC) C, O, ND) N, O, CE) none of these

84. Place the elements Ge, Br, and Ar in order of increasing atomic radius.A) Ge, Br, ArB) Ar, Br, GeC) Br, Ar, GeD) Ge, Ar, BrE) Br, Ge, Ar

85. Which element is most likely to form an ion with a charge of 2+?A) BrB) MgC) KD) OE) B

86. Which two elements are most likely to have the same oxidation state in an ionic compound?A) Li, BeB) Cl, FC) S, CaD) Al, ClE) none of these

87. Which of the following sets has elements with the most nearly identical atomic radii?A) Ni, Fe, Co, MnB) Mg, K, Sr, CsC) Ne, Kr, Ar, HeD) Be, B, C, NE) Si, P, Se, Br

88. Researchers recently formed a new synthetic element with atomic number 110. Which of the following elements would have chemical properties most similar to this new element?A) MoB) RnC) PdD) LaE) Ti

89. The statement that the first ionization energy for an oxygen atom is lower than the first ionization energy for a nitrogen atom isA) consistent with the general trend relating changes in ionization energy across a period from left to right, because it is

easier to take an electron from an oxygen atom than from a nitrogen atom.B) consistent with the general trend relating changes in ionization energy across a period from left to right, because it is

harder to take an electron from an oxygen atom than from a nitrogen atom.C) inconsistent with the general trend relating changes in ionization energy across a period from left to right and due to the

fact that the oxygen atom has two doubly occupied 2p orbitals and nitrogen has only one.D) inconsistent with the general trend relating changes in ionization energy across a period from left to right and due to the

fact that oxygen has one doubly occupied 2p orbital and nitrogen does not.E) incorrect.

90. Sodium losing an electron is an ________ process, and fluorine losing an electron is an _______ process.A) endothermic, exothermicB) exothermic, endothermicC) endothermic, endothermicD) exothermic, exothermicE) More information is needed.

91. Which of the following statements is true about the ionization energy of Mg+?A) It will be equal to the ionization energy of Li.B) It will be equal to and opposite in sign to the electron affinity of Mg.C) It will be equal to and opposite in sign to the electron affinity of Mg+.D) It will be equal to and opposite in sign to the electron affinity of Mg2+.E) none of the above

92. Which statements about hydrogen are true?I. H has a lower ionization energy than He.

II. H– is smaller than H.

III. H has a higher effective nuclear charge than He.

IV. H is always a metal.

V. H does not have a second ionization energy.

A) I, VB) II, IVC) I, III, VD) II, IV, VE) I, III, IV, V

Use the following to answer questions 93-94:

Consider the following orderings.I. Al < Si < P < ClII. Be < Mg < Ca < SrIII. I < Br < Cl < FIV. Na+ < Mg2+ < Al3+ < Si4+

93. Which of these give(s) a correct trend in size?A) IB) II onlyC) IIID) IV onlyE) II, IV

94. Which of these give(s) a correct trend in ionization energy?A) III onlyB) I, II onlyC) I, IV onlyD) I, III, IVE) none of them

95. Which of the following exhibits the correct orders (increasing) for atomic radius and ionization energy, respectively?A) S, O, F, and F, O, SB) F, S, O, and O, S, FC) S, F, O, and S, F, OD) F, O, S, and S, O, FE) none of these

96. Which of the following statements is true of second ionization energies?A) That of Al is higher than that of Mg because Mg wants to lose the second electron, so it is easier to take the second

electron away.B) That of Al is higher than that of Mg because the electrons are taken from the same energy level, but the Al atom has one

more proton.C) That of Al is lower than that of Mg because Mg wants to lose the second electron, so the energy change is greater.D) That of Al is lower than that of Mg because the second electron taken from Al is in a p orbital, so it is easier to take away.E) The second ionization energies are equal for Al and Mg.

Answer Key1. F 11. B 21. E 31. D 41. A 51. E 61. E 71. E 81. B 91. D2. B 12. B 22. C 32. C 42. C 52. C 62. C 72. A 82. B 92. C3. A 13. B 23. C 33. D 43. D 53. B 63. E 73. B 83. C 93. B4. B 14. A 24. A 34. C 44. B 54. A 64. A 74. D 84. B 94. D5. D 15. D 25. B 35. C 45. D 55. D 65. E 75. B 85. B 95. D6. D 16. D 26. B 36. A 46. B 56. E 66. C 76. C 86. B 96. B7. D 17. B 27. C 37. A 47. E 57. E 67. B 77. B 87. A8. C 18. C 28. C 38. A 48. A 58. A 68. D 78. A 88. C9. E 19. B 29. A 39. E 49. A 59. D 69. C 79. B 89. D10. B 20. A 30. E 40. B 50. B 60. D 70. B 80. C 90. C