AP Chemistry
Chapter 7 Periodic Properties of the Elements
Chapter 7. Periodic Properties of the Elements
Sample Exercise 7.1 (p. 264)
Natural gas used in home heating and cooking is odorless. Because natural gas leaks pose the danger of
explosion or suffocation, various smelly substances are added to the gas to allow detection of a leak. One such
substance is methyl mercaptan, CH3SH, whose structure is shown below. Use Figure 7.7 to predict the lengths
of the C-S, C-H, and S-H bonds in this molecule.
Practice Exercise 1 (7.1)
Hypothetical elements X and Y form a molecule XY2, in which both Y atoms are bonded to atom X (and not to
each other). The X-X distance in the elemental form of X is 2.04 Å, and the Y-Y distance in elemental Y is 1.68
Å. What would you predict for the X-Y distance in the XY2 molecule?
a) 0.84 Å
b) 1.02 Å
c) 1.86 Å
d) 2.70 Å
e) 3.72 Å
Practice Exercise 2 (7.1)
Using Figure 7.7, predict which will be greater, the P-Br bond length in PBr3 or the As-Cl bond length in AsCl3.
Sample Exercise 7.2 (p. 265)
Referring to a periodic table, arrange (as much as possible) the following atoms in order of increasing size:
16S, 33As, 34Se. (Atomic numbers are given for the elements to help you locate them quickly in the periodic
table.)
15P,
Practice Exercise 1 (7.2)
By referring to the periodic table, but not to Figure 7.7, place the following atoms in order of increasing bonding
atomic radius: N, O, P, Ge.
a)
b)
c)
d)
e)
N < O < P < Ge
P < N < O < Ge
O < N < Ge < P
O < N < P < Ge
N < P < Ge < O
Practice Exercise 2 (7.2)
Arrange the following atoms in order of increasing atomic radius:
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11Na, 4Be, 12Mg.
AP Chemistry
Chapter 7 Periodic Properties of the Elements
Sample Exercise 7.3 (p. 265)
Arrange these atoms and ions in order of decreasing size: Mg2+, Ca2+, Ca.
Practice Exercise 1 (7.3)
Arrange the following atoms and ions in order of increasing ionic radius: F, S2-, Cl, and Se2-.
a)
b)
c)
d)
e)
F < S2- < Cl < Se2F < Cl < S2- < Se2F < S2- < Se2- < Cl
Cl < F < Se2- < S2S2- < F < Se2- < Cl
Practice Exercise 2 (7.3)
Which of the following atoms and ions is largest: S2-, S, O2-?
Sample Exercise 7.4 (p. 267)
Arrange the ions S2-, Cl-, K+ and Ca2+ in order of decreasing size.
Practice Exercise 1 (7.4)
Arrange the following atoms and ions in order of increasing ionic radius: Br-, Rb+, Se2-, Sr2+, Te2-.
a) Sr2+ < Rb+ < Br-- < Se2- < Te2b) Br- < Sr2+ < Se2- < Te2- < Rb+
c) Rb+ < Sr2+ < Se2- < Te2- < Brd) Rb+ < Br- < Sr2+ < Se2- < Te2e) Sr2+ < Rb+ < Br- < Te2 < Se2Practice Exercise 2 (7.4)
Which of the following ions is largest? Rb+, Sr2+, or Y3+?
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AP Chemistry
Chapter 7 Periodic Properties of the Elements
Sample Exercise 7.5 (p. 269)
Three elements are indicated in the periodic table below. Based on their locations, predict the one with the
largest second ionization energy.
Practice Exercise 1 (7.5)
The third ionization energy of bromine is the energy required for which of the following processes?
a)
b)
c)
d)
e)
Br(g)  Br+(g) + eBr+(g)  Br2+(g) + eBr(g)  Br2+(g) + 2 eBr(g)  Br3+(g) + 3 eBr2+(g)  Br3+(g) + ePractice Exercise 2 (7.5)
Which will have the greater third ionization energy, Ca or S?
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AP Chemistry
Chapter 7 Periodic Properties of the Elements
Sample Exercise 7.6 (p. 270)
Referring to a periodic table, arrange the following atoms in order of increasing first ionization energy: Ne, Na,
P, Ar, K.
Practice Exercise 1 (7.6)
Consider the following statements about first ionization energies:
(i) Because the effective nuclear charge for Mg is greater than that for Be, the first ionization energy of
Mg is greater than that of Be.
(ii) The first ionization energy of O is less than that of N bcause in O we must pair electrons in the 2p
orbitals.
(iii) The first ionization energy of Ar is less than that of Ne because a 3p electron in Ar is farther from the
nucleus than a 2p electron in Ne.
Which of the statements (i), (ii), and (iii) is or are true?
a) Only one statement is true.
b) Statements (i) and (ii) are true.
c) Statements (i) and (iii) are true.
d) Statements (ii) and (iii) are true.
e) All three statements are true.
Practice Exercise 2 (7.6)
Which hs the lowest first ionization energy, B, Al, C, or Si? Which has the highest first ionization energy?
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AP Chemistry
Chapter 7 Periodic Properties of the Elements
Sample Exercise 7.7 (p. 271)
Write the electron configuration for the
a)
Ca2+ ion;
b)
Co3+ ion;
c)
S2- ion.
Practice Exercise 1 (7.7)
The ground state electron configuration of a Tc atom is [Kr]5s24d5. What is the electron configuration of a Tc3+
ion?
a) [Kr]4d4
b) [Kr]5s24d2
c) [Kr]5s14d3
d) [Kr]5s24d8
e) [Kr]4d10
Practice Exercise 2 (7.7)
Write the electron configuration for the
a)
Ga3+ ion;
b)
Cr3+ ion;
c)
Br- ion.
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AP Chemistry
Chapter 7 Periodic Properties of the Elements
Sample Exercise 7.8 (p. 276)
a)
Would you expect scandium oxide to be a solid, liquid, or gas at room temperature?
b)
Write the balanced chemical equation for the reaction of scandium oxide with nitric acid.
Practice Exercise 1 (7.8)
Suppose that a metal oxide of formula M2O3 were soluble in water. What would be the major product or
products of dissolving the substance in water?
a)
b)
c)
d)
e)
MH3(aq) + O2(g)
M(s) + H2(g) + O2(g)
M3+(aq) + H2O2(aq)
M(OH)2(aq)
M(OH)3(aq)
Practice Exercise 2 (7.8)
Write the balanced chemical equation for the reaction between copper(II) oxide and sulfuric acid.
Sample Exercise 7.9 (p. 277)
Write the balanced chemical equations for the reactions of solid selenium dioxide with
a)
water
b)
aqueous sodium hydroxide
Practice Exercise 1 (7.9)
Consider the following oxides: SO2, Y2O3, MgO, Cl2O, N2O5. How many are expected to form acidic solutions
in water?
a) 1
b) 2
c) 3
d) 4
e) 5
Practice Exercise 2 (7.9)
Write the balanced chemical equation for the reaction of solid tetraphosphorus hexoxide with water.
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AP Chemistry
Chapter 7 Periodic Properties of the Elements
Sample Exercise 7.10 (p. 280)
Write balanced chemical equations that predict the reactions of cesium metal with
a)
Cl2(g)
b)
H2O(l)
c)
H2(g)
Practice Exercise 1 (7.10)
Consider the following three statements about the reactivity of an alkali metal M with oxygen gas:
(i) Based on their positions in the periodic table, the expected product is the ionic oxide M2O.
(ii) Some of the alkali metals produce metal peroxides or metal superoxides when they react with oxygen.
(iii) When dissolved in water, an alkali metal oxide produces a basic solution.
Which of the statements (i), (ii), and (iii) is or are true?
a) Only one statement is true.
b) Statements (i) and (ii) are true.
c) Statements (i) and (iii) are true.
d) Statements (ii) and (iii) are true.
e) All three statements are true.
Practice Exercise 2 (7.10)
Write a balanced chemical equation that predicts the products of the reaction between potassium metal and
elemental sulfur.
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AP Chemistry
Chapter 7 Periodic Properties of the Elements
Sample Integrative Exercise 7 (p. 287)
The element bismuth (Bi, atomic number 83) is the heaviest member of group 5A. A salt of the element,
bismuth subsalicylate, is the active ingredient in Pepto-Bismol, an over-the-counter medication for gastric
distress.
1. The covalent atomic radii of thallium (Tl) and lead (Pb) are 1.48 Å and 1.47 Å, respectively.
Using these values what might you expect for the bonding atomic radius of bismuth?
2. What accounts for the general increase in atomic radius going down the group 5A elements?
3. Another major use of bismuth has been as an ingredient in low-melting metal alloys, such as those used in
fire sprinkler systems and in typesetting. The element itself is a brittle white crystalline solid.
How do these characteristics fit with the fact that bismuth is in the same periodic group with such
nonmetallic elements as nitrogen and phosphorus?
4. Bi2O3 is a basic oxide. Write a balanced equation for its reaction with dilute nitric acid. If 6.77 g of Bi 2O3
is dissolved in dilute acidic solution to make up 500 mL of solution, what is the molarity of the Bi3+ ion?
5.
209
Bi is the heaviest stable isotope of any element. How many protons and neutrons are present in this
nucleus?
6. The density of Bi at 25oC is 9.808 g/cm3. How many Bi atoms are present in a cube of the element that is
5.00 cm on each edge? How many moles of the element are present?
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