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PARALLEL EXERCISES

The exercises in groups A and B cover the same concepts. Solutions to group A exercises are located in appendix E.
Group A Group B
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1. A neutron with a mass of 1.68 × 10 kg moves from a nuclear 1. An electron with a mass of 9.11 × 10 kg has a velocity of 4.3 ×
6
3
reactor with a velocity of 3.22 × 10 m/s. What is the de Broglie 10 m/s in the innermost orbit of a hydrogen atom. What is the
wavelength of the neutron? de Broglie wavelength of the electron?
2. Calculate the energy (a) in eV and (b) in joules for the sixth 2. Calculate the energy (a) in eV and (b) in joules of the third
energy level (n = 6) of a hydrogen atom. energy level (n = 3) of a hydrogen atom.
3. How much energy is needed to move an electron in a hydrogen 3. How much energy is needed to move an electron in a hydrogen
atom from n = 2 to n = 6? Give the answer (a) in joules and atom from the ground state (n = 1) to n = 3? Give the answer
(b) in eV. (See Figure 8.11 for needed values.) (a) in joules and (b) in eV.
4. What frequency of light is emitted when an electron in a 4. What frequency of light is emitted when an electron in a
hydrogen atom jumps from n = 6 to n = 2? What color would hydrogen atom jumps from n = 2 to the ground state (n = 1)?
you see?
5. How much energy is needed to completely remove the electron 5. How much energy is needed to completely remove an electron
from a hydrogen atom in the ground state? from n = 2 in a hydrogen atom?
7
6. Thomson determined the charge-to-mass ratio of the electron to 6. If the charge-to-mass ratio of a proton is 9.58 × 10 coulomb/
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be –1.76 × 10 coulomb/kilogram. Millikan determined the kilogram and the charge is 1.60 × 10 coulomb, what is the
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charge on the electron to be –1.60 × 10 coulomb. According mass of the proton?
to these findings, what is the mass of an electron?
7. Assume that an electron wave making a standing wave in a 7. An electron wave making a standing wave in a hydrogen atom
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hydrogen atom has a wavelength of 1.67 × 10 m. Considering has a wavelength of 8.33 × 10 m. If the mass of the electron is
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the mass of an electron to be 9.11 × 10 kg, use the de Broglie 9.11 × 10 kg, what is the velocity of the electron according to
equation to calculate the velocity of an electron in this orbit. the de Broglie equation?
8. Using any reference you wish, write the complete electron 8. Using any reference you wish, write the complete electron
configurations for (a) boron, (b) aluminum, and (c) potassium. configurations for (a) nitrogen, (b) phosphorus, and (c) chlorine.
9. Explain how you know that you have the correct total number of 9. Explain how you know that you have the correct total number of
electrons in your answers for 8a, 8b, and 8c. electrons in your answers for 8a, 8b, and 8c.
10. Refer to Figure 8.16 only, and write the complete electron 10. Referring to Figure 8.16 only, write the complete electron
configurations for (a) argon, (b) zinc, and (c) bromine. configuration for (a) neon, (b) sulfur, and (c) calcium.
11. Lithium has two naturally occurring isotopes: lithium-6 and 11. Boron has two naturally occurring isotopes, boron-10 and
lithium-7. Lithium-6 has a mass of 6.01512 relative to carbon-12 boron-11. Boron-10 has a mass of 10.0129 relative to carbon-12
and makes up 7.42 percent of all naturally occurring lithium. and makes up 19.78 percent of all naturally occurring boron.
Lithium-7 has a mass of 7.016 compared to carbon-12 and makes Boron-11 has a mass of 11.00931 compared to carbon-12 and
up the remaining 92.58 percent. According to this information, makes up the remaining 80.22 percent. What is the atomic
what is the atomic weight of lithium? weight of boron?
12. Identify the number of protons, neutrons, and electrons in the 12. Identify the number of protons, neutrons, and electrons in the
following isotopes: following isotopes:
12
14
(a) 6 C (a) 7 N
7
1
(b) 1 H (b) 3 Li
40
35
(c) 18 Ar (c) 17 C
2
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(d) 1 H (d) 20 Ca
63
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(e) 79 Au (e) 29 Cu
230
235
(f) 92 U (f) 92 U
13. Identify the period and the family in the periodic table for the 13. Identify the period and the family in the periodic table for the
following elements: following elements:
(a) Radon (a) Xenon
(b) Sodium (b) Potassium
(c) Copper (c) Chromium
(d) Neon (d) Argon
(e) Iodine (e) Bromine
(f) Lead (f) Barium

226 CHAPTER 8 Atoms and Periodic Properties 8-24