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45. Hydrogen, with its one electron, can produce a line spectrum 9. Why does the carbon-12 isotope have a whole number mass but
with four visible colors because not the other isotopes?
a. an isotope of hydrogen has four electrons. 10. What do the members of the noble gas family have in common?
b. electrons occur naturally with four different colors. What are their differences?
c. there are multiple energy levels that an electron can occupy.
11. How are the isotopes of an element similar? How are they
d. electrons are easily scattered.
different?
46. A photon is emitted from the electronic structure of an atom
12. What patterns are noted in the electron structures of elements
when an electron
found in a period and in a family in the periodic table?
a. jumps from a higher to a lower energy level.
b. jumps from a lower to a higher energy level.
c. reverses its spin by 180°.
d. is removed from an atom by a high quantum of energy. FOR FURTHER ANALYSIS
47. Which of the following represents a hydrogen isotope?
1
a. H 1. Evaluate Millikan’s method for finding the charge of an

1
2 electron. Are there any doubts about the results of using this
b. H

1
3 technique?
c. H 2. What are the significant similarities and differences between the

1
d. All of the above are correct.
isotopes of a particular element?
12
14
48. In what are atoms of 6 C and 6 C different?
3. Thomson’s experiments led to the discovery of the electron.
a. Number of protons
Analyze how you know for sure that he discovered the electron.
b. Number of neutrons
4. Describe a conversation between yourself and another person as
c. Number of electrons
you correct her belief that atomic weight has something to do
d. None of the above is correct.
with gravity.
49. An atom has 6 protons, 6 electrons, and 6 neutrons, so the
5. Analyze the significance of the observation that matter only
isotope symbol is
18 emits and absorbs energy in discrete units.

a. Mg
12
12 6. Describe several basic differences between the Bohr and

b. Mg
12
12 quantum mechanics models of the atom.
c. 6 C
12
d. 6 C
Answers INVITATION TO INQUIRY
1. a 2. c 3. d 4. d 5. c 6. a 7. d 8. b 9. c 10. b 11. d 12. a 13. b 14. a
15. c 16. b 17. c 18. d 19. a 20. c 21. b 22. a 23. b 24. c 25. c 26. a Too Small to See?
27. c 28. d 29. b 30. d 31. b 32. d 33. b 34. a 35. d 36. c 37. d 38. c
As Rutherford knew when he conducted his famous experiment with
39. c 40. d 41. b 42. c 43. b 44. c 45. c 46. a 47. d 48. b 49. c
radioactive particles and gold foil, the structure of an atom is too small
to see, so it must be inferred from other observations. To illustrate this
process, pour 50 mL of 95 percent ethyl alcohol (or some other almost
QUESTIONS FOR THOUGHT pure alcohol) into a graduated cylinder. In a second graduated cylin-
der, measure 50 mL of water. Mix thoroughly and record the volume
1. Describe the experimental evidence that led Rutherford to the of the combined liquids. Assuming no evaporation took place, is the
concept of a nucleus in an atom. result contrary to your expectation? What question could be asked
2. What is the main problem with a solar system model of the atom? about the result?
3. Compare the size of an atom to the size of its nucleus. Answers to questions about things that you cannot see often
4. An atom has 11 protons in the nucleus. What is the atomic require a model that can be observed. For example, a model might
number? What is the name of this element? What is the electron represent water and alcohol molecules by using beans for alcohol mol-
configuration of this atom? ecules and sand for water molecules. Does mixing 50 mL of beans and
5. Why do the energies of electrons in an atom have negative 50 mL of sand result in 100 mL of mixed sand and beans? Explain the
values? (Hint: It is not because of the charge of the electron.) result of mixing alcohol and water based on your observation of mix-
6. What is similar about the Bohr model of the atom and the quantum ing beans and sand.
mechanical model? What are the fundamental differences? To continue this inquiry, fill a water glass to the brim with
7. What is the difference between a hydrogen atom in the ground water. Add a small amount of salt to the water. You know that two
state and one in the excited state? materials cannot take up the same space at the same time, so what
8. Which of the following are whole numbers, and which are not happened to the salt? How can you test your ideas about things that
whole numbers? Explain why for each. are too tiny to see?
(a) Atomic number
(b) Isotope mass
(c) Mass number
(d) Atomic weight
8-23 CHAPTER 8 Atoms and Periodic Properties 225