4
CHAPTER
REVIEW
4
REVIEW ANSWERS
1. alkaline-earth metals
2. halogens
3. metals
4. electron affinity
5. actinides
6. answers should involve the
transmutation of one element
to another by a change in the
number of protons in its nucleus.
7. alkali metals
8. electron shielding
9. electronegativity and ionization
energy
10. Answers should discuss particle
accelerators and the colliding
of particles at very high speeds
to produce elements of higher
atomic numbers.
11. noble gases
12. seven
13. Answers may include brass, steel,
sterling silver, pig iron, etc.
14. Moseley arranged the elements
according to their atomic numbers, while Mendeleev had
arranged them based on their
atomic mass.
15. He left gaps for the elements that
he predicted would be discovered
and which would have certain
properties.
16. His success in predicting the
properties of elements that
had not yet been discovered
gave him credibility.
17. The completion of an energy
level determines the points at
which the elements begin new
periods.
18. It has two valence electrons and
six occupied energy levels.
19. With only one proton and one
electron, hydrogen does not
exhibit the same properties
shared by the elements making
up any of the groups in the periodic table.
150
CHAPTER REVIEW
USING KEY TERMS
UNDERSTANDING KEY IDEAS
1. What group of elements do Ca, Be, and Mg
belong to?
14. How was Moseley’s arrangement of the
elements in the periodic table different
from Mendeleev’s?
2. What group of elements easily gains one
valence electron?
3. What category do most of the elements of
15. What did the gaps on Mendeleev’s periodic
the periodic table fall under?
table represent?
4. What is the term for the energy released
16. Why was Mendeleev’s periodic table
when an atom gains an electron?
accepted by most chemists?
5. What are elements 90–103 called?
17. What determines the horizontal arrange-
ment of the periodic table?
6. Give an example of a nuclear reaction.
Describe the process by which it takes place.
18. Why is barium, Ba, placed in Group 2 and
in Period 6?
7. What are elements in the first group of the
periodic table called?
Tour of the Periodic Table
8. What atomic property affects periodic
19. Why is hydrogen in a class by itself?
trends down a group in the periodic table?
20. All halogens are highly reactive. What
causes these elements to have similar
chemical behavior?
9. What two atomic properties have an
increasing trend as you move across a
period?
10. Write a paragraph describing in
How Are Elements Organized?
21. What property do the noble gases share?
How do the electron configurations of the
noble gases give them this shared property?
WRITING
SKILLS
your own words how synthetic
elements are created. Discuss
what modification has to be made to the
equipment in order to synthesize superheavy elements.
22. How do the electron configurations of the
transition metals differ from those of the
metals in Groups 1 and 2?
23. Why is carbon, a nonmetal element, added
11. Which group of elements has very high
to iron to make nails?
ionization energies and very low electron
affinities?
24. If an element breaks when it is struck with a
12. How many valence electrons does a fluorine
atom have?
13. Give an example of an alloy.
hammer, could it be a metal? Explain.
25. Why are the lanthanides and actinides
placed at the bottom of the periodic table?
26. Explain why the main-group elements are
also known as representative elements.
150
Assignment Guide
Section
1
2
3
4
Chapter 4 • The Periodic Table
Questions
12, 14–18, 40, 42, 52, 57
1–3, 5, 7, 13, 19–26, 41, 44–46, 48, 50,
51, 55
4, 8, 9, 11, 27–33, 43, 47, 49, 54,
58–64
6, 10, 34, 39, 56
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Trends in the Periodic Table
Where Did the Elements Come From?
27. What periodic trends exist for ionization
34. How does nuclear fusion generate energy?
energy? How does this trend relate to
different energy levels?
28. Why don’t chemists define atomic radius as
the radius of the electron cloud that surrounds a nucleus?
29. How does the periodic trend of atomic
radius relate to the addition of electrons?
30. What happens to electron affinity as you
move across a period beginning with Group
1? Why do these values change as they do?
31. Identify which trend diagram below
35. What happens in the nucleus of an atom
when a transmutation takes place?
36. Why are technetium, promethium, and
neptunium considered natural elements
even though they are not found on Earth?
37. Why must a synchrotron be used to create
a superheavy element?
38. What role did supernovae play in creating
the natural elements?
39. What two elements make up most of the
matter in a star?
describes atomic radius.
Increases
identify the period and group in which
each of the following elements is located.
1
a. [Rn]7s
2
b. [Ar]4s
2
6
c. [Ne]3s 3p
Decreases
42. When 578 kJ/mol of energy is supplied, Al
loses one valence electron. Write the
electron configuration of the ion that forms.
Decreases
Increases
c.
41. Which of the following ions has the electron
configuration of a noble gas: Ca+ or Cl−?
(Hint: Write the electron configuration for
each ion.)
Decreases
b.
MIXED REVIEW
40. Without looking at the periodic table,
Increases
a.
REVIEW ANSWERS
continued
32. What periodic trends exist for electronega-
43. Name three periodic trends you encounter
in your life.
44. How do the electron configurations of the
lanthanide and actinide elements differ from
the electron configurations of the other
transition metals?
45. Use the periodic table to describe the chem-
tivity? Explain the factors involved.
33. Why are the melting and boiling points of
mercury almost the lowest of the elements
in its period?
ical properties of the following elements:
a. iodine, I
b. krypton, Kr
c. rubidium, Rb
151
Copyright © by Holt, Rinehart and Winston. All rights reserved.
20. All halogens have seven valence
electrons and are therefore one
electron short of having a full
valence shell. As a result, they
readily react to acquire this one
electron.
21. Noble gases do not normally
react with other elements because
of the stability resulting from
their electron configurations.
22. The outer electrons of Groups 1
and 2 are in s orbitals. The outer
electrons of the transition metals
are in d orbitals and s orbitals.
23. Pure iron is too soft to make
nails. Adding carbon produces a
harder alloy.
24. Some metals are brittle.
Therefore, this element may be
a metal if it is shown to be an
excellent conductor of electricity.
25. This arrangement keeps the
periodic table conveniently
narrow.
26. They exhibit all the properties
characteristic of the elements.
27. Ionization energy slightly
decreases as you move down a
group and increases significantly
as you move across a period.
Increased distance from the
nucleus allows removal of an
electron using less energy.
28. Because an electron cloud has no
definite boundary, an exact radius
is impossible to measure.
29. As electrons are added across
a period, they are entering the
same principal energy level. The
increasing nuclear charge pulls
these electrons closer, making
the atoms progressively smaller
across a period. As electrons are
added down a group, they are
entering another principal energy
level, thus increasing the size of
the atom.
30. Electron affinity generally
increases because the effective
nuclear charge increases. Electron
shielding does not play a role
because electrons are not added
to inner energy levels.
Chapter 4 • The Periodic Table
151
REVIEW ANSWERS
continued
31. c
32. Electronegativity decreases as
you move down a group because
of the increasing electron shielding and increases as you move
across a period because of the
increasing effective nuclear
charge.
33. Because the d orbitals are completely filled, mercury forms
weaker bonds than most of the
other elements in Period 6.
34. The mass of the fused nuclei is
less than that of the mass of the
nuclei that created it. This mass
is converted to energy during
fusion.
35. The number of protons either
increases or decreases during a
nuclear reaction, producing a
different element.
36. These elements can be found
elsewhere in the universe and
are therefore natural.
37. Only a synchrotron can accelerate
nuclei to energies high enough to
result in fusion involving massive
nuclei.
38. Elements heavier than iron were
formed in supernovae.
39. hydrogen and helium
40. a. Period 7, Group 1
b. Period 4, group 2
c. Period 3, group 18
41. Cl–
42. [Ne]3s2
43. Answers will vary but could
include, for example, the pattern
of seasons, the repeating school
year, the progression of weeks,
or the pattern of daily meals.
44. The lanthanide and actinide
elements have partially filled
f-electron shells.
45. a. A nonmetal in Group 17, it
needs one electron to achieve
a noble-gas configuration,
which means it is likely to
react with elements with
which it can obtain one electron, such as an alkali metal.
It has a high ionization energy,
and thus the formation of positive ions is not likely.
152
46. The electron configuration of argon differs
from those of chlorine and potassium by
one electron each. Compare the reactivity of
these three elements, and relate them to
their electron configurations.
in the periodic table. Does strontium share
more properties with yttrium or barium?
Explain your answer.
54. Examine the following diagram.
47. What trends were first used to classify the
elements? What trends were discovered
after the elements were classified in the
periodic table?
48. Among the main-group elements, what is
the relationship between group number and
the number of valence electrons among
group members?
CRITICAL THINKING
Explain why the structure shown on the
right was drawn to have a smaller radius
than the structure on the left.
ALTERNATIVE ASSESSMENT
49. Consider two main-group elements, A and
B. Element A has an ionization energy of
419 kJ/mol. Element B has an ionization
energy of 1000 kJ/mol. Which element is
more likely to form a cation?
55. Select an alloy. You can choose one men-
50. Argon differs from both chlorine and potas-
sium by one proton each. Compare the electron configurations of these three elements
to explain the reactivity of these elements.
51. While at an amusement park, you inhale
helium from a balloon to make your voice
higher pitched. A friend says that helium
reacts with and tightens the vocal cords to
make your voice have the higher pitch.
Could he be correct? Why or why not?
tioned in this book or find another one by
checking the library or the Internet. Obtain
information on how the alloy is made.
Obtain information on how the alloy is
used for practical purposes.
56. Construct a model of a synchrotron. Check
the library and Internet for information
about synchrotrons. You may want to
contact a synchrotron facility directly to
find out what is currently being done in
the field of synthetic elements.
57. In many labeled foods, the mineral content
52. In his periodic table, Mendeleev placed Be,
Mg, Zn, and Cd in one group and Ca, Sr, Ba,
and Pb in another group. Examine the electron configurations of these elements, and
explain why Mendeleev grouped the elements this way.
53. The atomic number of yttrium, which fol-
lows strontium in the periodic table, exceeds
the atomic number of strontium by one.
Barium is 18 atomic numbers after strontium but it falls directly beneath strontium
is stated in terms of the mass of the element,
in a stated quantity of food. Examine the
product labels of the foods you eat.
Determine which elements are represented
in your food and what function each element serves in the body. Make a poster of
foods that are good sources of minerals that
you need.
CONCEPT MAPPING
58. Use the following terms to create a concept
map: atomic number, atoms, electrons, elements, periodic table, and protons.
152
Chapter 4 • The Periodic Table
Copyright © by Holt, Rinehart and Winston. All rights reserved.
REVIEW ANSWERS
continued
FOCUS ON GRAPHING
Study the graph below, and answer the questions that follow.
For help in interpreting graphs, see Appendix B, “Study Skills for Chemistry.”
59. What relationship is represented in the
Atomic Radii of Main-Block Elements
graph shown?
250
60. What do the numbers on the y-axis
200
62. Why is the axis representing group
number drawn the way it is in going
from Group 2 to Group 13?
63. Which period shows the greatest change
Atomic radius (pm)
61. In every Period, which Group contains
the element with the greatest atomic
radius?
Cs
Rb
represent?
150
K
Na
Period 6
Period 5
Period 4
Period 3
Li
100
Period 2
50
H
He
Period 1
in atomic radius?
64. Notice that the points plotted for the
elements in Periods 5 and 6 of Group 2
overlap. What does this overlap indicate?
0
1
2
13
14
15
16
17
18
Group number
TECHNOLOGY AND LEARNING
65. Graphing Calculator
Graphing Atomic Radius Vs. Atomic Number
The graphing calculator can run a program
that graphs data such as atomic radius versus atomic number. Graphing the data
within the different periods will allow you
to discover trends.
Go to Appendix C. If you are using a TI-83
Plus, you can download the program and
data sets and run the application as directed.
Press the APPS key on your calculator, then
choose the application CHEMAPPS. Press 8,
then highlight ALL on the screen, press 1,
then highlight LOAD and press 2 to load the
data into your calculator. Quit the application, and then run the program RADIUS. For
L1, press 2nd and LIST, and choose ATNUM.
For L2, press 2nd and LIST and choose
ATRAD.
If you are using another calculator, your
teacher will provide you with keystrokes and
data sets to use.
a. Would you expect any atomic number to
have an atomic radius of 20 pm? Explain.
b. A relationship is considered a function if it
can pass a vertical line test. That is, if a vertical line can be drawn anywhere on the graph
and only pass through one point, the relationship is a function. Does this set of data represent a function? Explain.
c. How would you describe the graphical relationship between the atomic numbers and
atomic radii?
153
Chapter Resource File
• Chapter Test
b. A nonmetal of low reactivity
in Group 18, it has a filled
outer-energy level, so there
is little tendency to lose, gain,
or share electrons.
c. A reactive metal in Group 1,
it has a low ionization energy
because the loss of an electron
to form a positive ion gives
it a noble-gas configuration.
46. Argon has a complete energy
level of electrons, and therefore
is not reactive. Chlorine’s electron configuration is one short
of a full shell, so it has a tendency to react with elements
from which it can gain one
electron. Potassium has only
a single valence electron, so it
readily reacts to lose that electron.
47. Elements were first classified by
reactivity and atomic mass. The
modern periodic table has trends
of atomic size, electron configuration, ionization energy, and electron affinity, among other factors
not covered in this chapter.
48. Groups 1 and 2 have the same
number of valence electrons as
their group number. Groups
13–18 have n–10 valence electrons, n being the group number.
49. Element A is more likely to lose
an electron and become a cation
because it has a lower ionization
energy.
50. As a noble gas with a full valence
shell, 3s23p6, argon is unreactive.
Chlorine has one less electron
than argon, 3s23p5, so it tends to
react by gaining one electron to
form an anion with a 1– charge.
Potassium has one more electron
than argon, 3s23p64s1, so it tends
to react by losing one electron to
form a cation with a 1+ charge.
Answers continued on p. 155A–B
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 4 • The Periodic Table
153
STANDARDIZED
TEST PREP
4
Question 3 Choice C is the correct answer because the stable
structure of noble gases means that
it takes more energy to remove
electrons. Choices A and B are
wrong because noble gases have
relatively small radii and low electron affinities. Choice D is incorrect because noble gases do not
form either anions or cations.
UNDERSTANDING CONCEPTS
7
Directions (1–4): For each question, write on a
separate sheet of paper the letter of the correct
answer.
1
2
Question 5 Filling in the gaps
demonstrated the predictive value
of the table. That it could be used
to determine the properties of elements not known to exist supported the system of classification
used in the table.
Question 8 The correct answer is
D. Beryllium and strontium are in
the same column, so they have the
same valence electron arrangement. Although boron and beryllium are close together, they have
different numbers of valence electrons that determine the element's
properties.
3
What is the outermost occupied energy level
in atoms of the elements in Period 4?
READING SKILLS
Directions (8–10): Read the passage below. Then
answer the questions.
Which of the following elements is formed
in stars?
A. curium
C. gold
B. einsteinium
D. mendelevium
The atomic number of beryllium is one less
than that of boron, which follows it on the periodic table. Strontium, which is directly below
beryllium in period 5 of the periodic table has
34 more protons and 34 more electrons than
beryllium. However, the properties of beryllium
resemble the much larger strontium more than
those of similar-sized boron.
Why are the Group 17 elements, the
halogens, the most reactive of the nonmetal
elements?
F. They have the largest atomic radii.
G. They have the highest ionization energies.
H. They are the farthest right on the periodic
table.
I. They require only one electron to fill their
outer energy level.
Which of the following is a property of
noble gases as a result of their stable electron
configuration?
A. large atomic radii
B. high electron affinities
C. high ionization energies
D. a tendency to form both cations
and anions
4
Which of these is a transition element?
F. Ba
H. Fe
G. C
I. Xe
Directions (5–7): For each question, write a short
response.
Question 10 Properties are based
on electron structure, which is the
organizing principle of the
columns. Electron structure varies
across the rows of the table, but
the electron structure is the same
in each column. Properties of the
element indicate its column but
not its row.
154
STANDARDIZED TEST PREP
5
How did the discovery of the elements that
filled the gaps in Mendeleev’s periodic table
increase confidence in the periodic table?
6
Why is iodine placed after tellurium on the
periodic table if the atomic mass of tellurium
is less than that of iodine?
8
The properties of beryllium are more similar
to those of strontium than those of boron
because
A. A strontium atom is larger than a boron
atom.
B. Strontium and beryllium are both reactive
nonmetals.
C. A strontium atom has more electrons
than a boron atom.
D. Strontium has the same number of
valence electrons as beryllium.
9
Beryllium and strontium are both located in
the second column of the periodic table. To
which of these classifications do they belong?
F. alkali metals
G. alkaline earth metals
H. rare earth metals
I. transition metals
0
Why is it easier to determine to which column of the periodic table an element belongs
than to determine to which row it belongs,
based on observations of its properties?
154
Answers
1.
2.
3.
4.
5.
C
I
C
H
The gaps were significant because they predicted
the properties of new elements that would be discovered. Their discovery demonstrated that the
table was a useful tool for organizing information
about atoms.
6. Because the periodic table is based on atomic
number, not atomic mass. The atomic number of
iodine is one higher than the atomic number of tellurium.
Chapter 4 • The Periodic Table
7.
8.
9.
10.
Level 4
D
G
It is easier to determine the column because all the
elements in a column have the same outer electron
structure and, therefore, similar properties.
Properties of elements across a row of the table
vary widely.
11. D
12. G
13. Ionization energy tends to increase from left to
right across the table because elements have
increasingly more protons so the attraction on the
outer electrons is stronger.
Copyright © by Holt, Rinehart and Winston. All rights reserved.