Chapter 18 Review: Properties of Atoms
Modified True/False
Indicate whether the sentence or statement is true or false. If false, change the identified word or phrase to make the sentence or
statement true.
____
1. The central core of an atom is called the hub. _________________________
____
2. The chart showing the classifications of elements according to their properties and increasing atomic numbers is called
the periodic table. _________________________
____
3. The mass of an electron is about equal to the mass of a proton. _________________________
____
4. Elements arranged in vertical columns in the periodic table are called periods. _________________________
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5. The region around the nucleus occupied by the electrons is called the negative zone. _________________________
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6. The symbol for chlorine is C. _________________________
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7. The maximum number of electrons in the second energy level of an atom is 4. _________________________
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8. Two isotopes of carbon are carbon-12 and carbon-14. These isotopes differ from one another by two protons.
_________________________
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9. Metals are good conductors of heat and electricity. _________________________
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10. Scientists believe that naturally occurring elements are manufactured within Mars. _________________________
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11. So far, scientists have confirmed the existence of six different quarks. _________________________
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12. In 1926, scientists developed the Bohr model of the atom that is in use today. _________________________
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13. The sum of the number of protons and neutrons in an atom is the mass number. _________________________
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14. The symbol for fluorine is Fe. _________________________
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15. A very stable electron arrangement in the outer energy level is characteristic of noble gases.
_________________________
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16. One proton and one electron are added to each element as you go across the periodic table.
_________________________
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17. Electron cloud models are used to show how electrons in the outer energy level are bonded when elements combine to
form compounds. _________________________
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18. The atomic number of an element is determined by its number of protons. _________________________
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19. According to present atomic theory, the location of an electron in an atom cannot be pinpointed exactly.
_________________________
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20. Moving from left to right in a row of the periodic table, metallic properties increase. _________________________
Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
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21. Each inner energy level of an atom has a maximum number of ____ it can hold.
a. electrons
c. quarks
b. neutrons
d. protons
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22. Dot diagrams are used to represent ____.
a. atomic numbers
b. atomic mass
c.
d.
isotopes
outer level electrons
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23. Particles of matter that make up protons and neutrons are ____.
a. electrons
c. quarks
b. isotopes
d. atoms
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24. A chemical symbol represents the ____ of an element.
a. name
c.
b. reaction
d.
group
structure
25. Horizontal rows of the periodic table are called ____.
a. clusters
c.
b. families
d.
groups
periods
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____
26. Atoms of the same element with different numbers of neutrons are called ____.
a. isotopes
c. metalloids
b. metals
d. radioactive elements
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27. A particle that moves around the nucleus is a(n) ____.
a. electron
c.
b. proton
d.
neutron
quark
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28. Elements that are gases, are brittle, and are poor conductors at room temperature are ____.
a. metals
c. metalloids
b. nonmetals
d. isotopes
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29. A ____ is used to accelerate protons in the study of subatomic particles.
a. tevatron
c. technology
b. termanite
d. television
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30. A certain atom has 26 protons, 26 electrons, and 30 neutrons. Its mass number is ____.
a. 26
c. 52
b. 30
d. 56
Short Answer
31. Explain why the noble gases are stable.
32. Compare the masses of protons, electrons, and neutrons.
33. Explain why some elements have one capital letter and others have a capital letter and one or two lowercase letters.
34. Why was it so difficult for scientists to find the sixth quark?
35. How are isotopes the same and how are they different?
36. Explain why the periodic table is such a useful tool.
37. Describe where the electrons are in the atom, where they have the least energy, and where they have the most energy.
38. Why is Ag the symbol for silver?
39. Two common quarks are called Up, with a charge of +2/3, and Down, with a charge of –1/3; Protons are made up of
three quarks. How many of each quark would make a proton?
40. Two common quarks are called Up, with a charge of +2/3, and Down, with a charge of –1/3. Neutrons are made up of
three quarks. How many of each quark would make a neutron?
41. Chlorine’s atomic mass is 35.453. List the two most reasonable isotopes of chlorine. Which one should be more
common?
42. A common radioactive isotope of carbon is carbon-14. How many protons and neutrons does it have?
43. One isotope of uranium is U-238. How many protons and neutrons does it have?
44. Cobalt’s atomic mass is 58.9332. What is the most common isotope of cobalt?
45. Use the periodic table to find the name, atomic number, and the average atomic mass of the following elements: F, O, P,
S.
46. Give the period and group for each of the following elements: F, O, P, S.
47. What is the name of each of the following elements, and classify it as a metal, a nonmetal, or a metalloid: Na, Ba, Ca,
La, Ti, Al, As, At, Ar.
48. Give the name for each of the following elements: Na, Fe, W, Ag, Sn, Sb, Pb, Au.
49. What is the difference between scaled-down models and scaled-up models?
50. What is unusual about the structure of hydrogen-1?
51. How many groups and how many periods make up the periodic table?
52. Why was the periodic table so named?
53. Who developed the first periodic table?
Figure 18-1
54.
55.
56.
57.
Do the elements shown in Figure 18-1 belong to the same period or the same group?
Are the elements in Figure 18-1 metals or nonmetals?
Are the properties of the two elements in Figure 18-1 similar or quite different?
At room temperature, will the elements in Figure 18-1 be solids, liquids, or gases?
Problem
58. Suppose that you have just discovered a new element and have named it neptunite. While studying your new element,
you find that it has two isotopes—neptunite-220 and neptunite-250. What is the average atomic mass of your new
element? (Assume that these two isotopes are present in equal amounts in nature.)
59. Assume that an element is composed of one isotope with a mass of 142 and another isotope with a mass of 145. For each
atom with a mass of 142 there are three atoms with a mass of 145. What is the average atomic mass of the element?
Answer Section
MODIFIED TRUE/FALSE
1. ANS: F, nucleus
2. ANS: T
3. ANS: F, neutron
4. ANS: F, groups
5. ANS: F, electron cloud
6. ANS: F, Cl
7. ANS: F, 8
8. ANS: F, neutrons
9. ANS: T
10. ANS: F, stars
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
MULTIPLE CHOICE
21.
A
22.
D
23.
C
24.
A
25.
D
26.
27.
28.
29.
30.
A
A
B
A
D
T
F, electron cloud
T
F, iron
T
T
F, dot diagrams
T
T
F, decrease
SHORT ANSWER
31. Their outer energy levels are full.
32. The mass of a proton and a neutron are about the same, and the electron is about 1,836 times smaller.
33. There are only 26 capital letters and more than 100 elements, so the lowercase letters are needed to help tell elements apart.
34. Its tracks in the bubble chamber were hard to detect because only about one billionth of a percent of the proton collisions
performed showed its presence.
35. Chemically they act the same and have the same number of protons and electrons. However, they have different numbers of
neutrons and different atomic masses.
36. It shows the relationship among the elements, and it can be used to predict similarities and differences among the elements.
37. Electrons go around the nucleus in a cloud. Energy is lowest close to the nucleus, and highest away from the nucleus.
38. Argentum is Latin for "silver."
39. 2 Up, 1 Down
40. 1 Up, 2 Down
41. Cl-35 and Cl-36; Cl-35 should be more common
42. 6 protons, 8 neutrons
43. 92 protons, 146 neutrons
44. CO-59
45. F, fluorine, 9, 18.998; O, oxygen, 8, 15.999; P, phosphorus, 15, 30.974; S, sulfur, 16, 32.066
46. F, period 2, Group 17; O, period 2, Group 16; P, period 3, Group 15; S, period 3, Group 16
47. Na, sodium, metal; Ba, barium, metal; Ca, calcium, metal; La, lanthanum, metal; Ti, titanium, metal; Al, aluminum, metal; As,
arsenic, metalloid; At, astatine, metalloid; Ar, argon, nonmetal
48. Na, sodium; Fe, iron; W, tungsten; Ag, silver; Sn, Tin; Sb, antimony; Pb, lead; Au, gold
49. Scaled-down models represent something too large to see all at once, or something that has not been built yet. Scaled-up models
represents things that are too small to see.
50. Hydrogen-1 contains no neutrons.
51. 18 groups, 7 periods
52. Because it shows a repeating pattern.
53. Dimitri Mendeleev
54. same group
55. metals
56. similar
57. solids
PROBLEM
58. 235 amu
59. 144.25