EXERCISES
_ _ 13. a diagram of a molecule that shows the chemical symbol of each atom and a dash
_ _ 14.
_
15.
_
16.
_ _ 17.
_
18.
_ _ 19.
_ _ 20.
_
21.
_ _ 22.
_ _ 23.
_ _ 24.
_ _ 25.
_ _ 26.
representing each pair of bonding electrons
a bond composed of one electron pair shared by two atoms
a bond composed of two electron pairs shared by two atoms
a bond composed of three electron pairs shared by two atoms
a single atom that bears a negative or positive charge as the result of gaining or losing valence electrons
a group of atoms held together by covalent bonds and having an overall positive or
negative charge
the ability of an atom to attract a shared pair of electrons
a method of indicating a partial positive and a partial negative charge in a chemical bond
a bond in which a pair of electrons is shared unequally
a bond in which a pair of electrons is shared equally
a molecule composed of two nonmetal atoms held together by a covalent bond
a bond in which an electron pair is shared but both electrons have been donated by
a single atom
th~ attraction between a H atom bonded to 0 or N, and a nonbonding electron pair
on an electronegative atom in another molecule
a model that explaiilll the shapes of molecules as a result of electron pairs about the
central atom repelling each other
the geometric shape formed by bonding and nonbonding electron pairs about the
central atom in a molecule
the geometric shape formed by atoms bonded to the central atom in a molecule
the angle formed by two atoms attached to the central atom in a molecule
Exe re ise s
4.
5.
6.
7.
.
·
,
.·
(m) electronegativity
(Sec. 12.6)
(n) formula unit (Sec. 12.1)
(o) hydrogen bond (Sec. 12.9)
(p) ionic bond (Sec. 12.1)
(q) molecular shape
(Sec. 12.10)
molecule (Sec. 12.1)
monoatomic ion (Sec. 12.5)
(t) nonbonding electrons
(r)
(s)
(Sec. 12.4)
(u)
(v)
(w)
(x)
(y)
(z)
nonpolar bond (Sec. 12.7)
octet rule (Sec. 12.1)
polar bond (Sec. 12.6)
polyatomic ion (Sec. 12.5)
single bond (Sec. 12.4)
structural formula
(Sec. 12.4)
(aa) triple bond (Sec. 12.4)
(ab) valence electrons
(Sec. 12.1)
(ac) VSEPR theory (Sec. 12.10)
10. State whether the representative particle in each of the fol-
lowing substances is an atom, a formula unit, or a molecule:
(a) xenon, Xe
(b) phosphorus, P4
(c) xenon trioxide, Xe03
(d) magnetite, Fe30 4
1. State the number of valence electrons for a potassium atom
3.
electron pair geometry
(Sec. 12.10)
Answers to odd-numbered Exercises are in Appendix I.
The Chemical Bond Concept (Sec. 12.1)
2.
(1)
349
and an iodine atom.
State the number of valence electrons for a hydrogen atom
and an iodine atom.
State the number of valence electrons for a potassium ion
and an iodide ion in an ionic bond.
State the number of valence electrons for a hydrogen atom
and an iodine atom in a covalent bond.
Predict whether each of the following is held together by
ionic or covalent bonds:
(a) aluminum chloride, AlC13 (b) water, H20
(c) sulfur trioxide, 503
(d) iron(II) sulfate, FeS04
Predict whether each of the following is held together by
ionic or covalent bonds:
(a) zinc bromide, ZnBr2
(b) carbon dioxide, C02
(c) iodine heptafluoride, IF7 (d) lead(II) sulfate, PbS04
State whether the representative particle in each of the following substances is a formula unit or a molecule:
(a) acetic acid, HC 2H 30 2
(b) chlorine dioxide, Cl02
(c) sodium chlorate, NaC103 (d) titanium(IV) oxide, Ti02
State whether the representative particle in each of the following substances is a formula unit or a molecule:
(a) methanol, CH30H
(b) cobaltous chloride, CoCI2
(c) acetone, CH3COCH3
(d) stannous carbonate, SnC03
State whether the representative particle in each of the following substances is an atom, a formula unit, or a molecule:
(a) propane, C3H 8
(b) platinum, Pt
(c) hematite, Fe20 3
(d) sulfur, S8
Ionic Bonds (Sec. 12.2)
11. Use the periodic table to predict an ionic charge for each of
12.
13.
14.
15.
16.
the following metal ions:
(a) Li ion
(b) Sr ion
(c) Al ion
(d) Pb ion
Use the periodic table to predict an ionic charge for each of
the following metal ions:
(a) Na ion
(b) Ba ion
(c) Ga ion
(d) Sn ion
Use the periodic table to predict the ionic charge for each of
the following nonmetal ions:
(a) Cl ion
(b) I ion
(c) S ion
(d) P ion
Use the periodic table to predict the ionic charge for each of
the following nonmetal ions:
(a) F ion
(b) Br ion
(c) Se ion
(d) Nion
Write out the electron configuration for each of the following metal ions:
(a) u+
(b) Al3 +
(c) Ca 2 +
(d) Mg2+
Write out the electron configuration for each of the following metal ions:
(a) Sc3 +
(b) K+
(c) Ti 4 +
(d) Ba2 +
350
CHAPTER 12
CHEMICAL BONDING
17. Write out the electron configuration for each of the following nonmetal ions:
(a) c1(c) 52-
(b) 1(d) p3-
18. Write out the electron configuration for each of the following nonmetal ions:
(b) 0 2 (a) Br2
(d) N 3 (c) Se 19. Refer to the periodic table and state the noble gas with
an electron configuration identical to each of the following ions:
(a)
s2 -
(c) K+
<h> c1-
(d) Ca2 +
20. Refer to the periodic table and state the noble gas with
an electron configuration identical to each of the following ions:
(b) Br(a) Se2 (d) Sr2 +
(c) Rb+
21. Whic~ noble gas is isoelectronic with each of the following
metal ions?
(a) u+
(c) Ca 2 +
(b) Al3 +
(d) Mg2 +
22. Which noble gas is isoelectronic with each of the following
metal ions?
(b) K+
(a) Sc 3 +
(d) Ba 2 +
(c) Ti4 +
23. Which noble gas is isoelectronic with each of the following
nonmetal ions?
(a) ci(c)
s2-
(b) 1(d) p3-
24. Which noble gas is isoelectronic with each of the following
nonmetal ions?
(a) Br(b) 0 2 (c) Se2 (d) N 3 2.5. In each of the following pairs, which has the larger radius?
(a) Li atom or Li ion
(b) Mg atom or Mg ion
(c) F atom or F ion
(d) 0 atom or 0 ion
26. In each of the following pairs, which has the larger radius?
(a) Al atom or Al ion
(c) Se atom or Se ion
(b) Pb atom or Pb ion
(d) N atom or N ion
27. Which of the following statements are false regarding
an ionic bond between cobalt and sulfur in a CoS
formula unit?
(a) Cobalt and sulfide ions bond by electrostatic attraction.
(b) Cobalt atoms gain electrons and sulfur atoms
lose electrons.
(c) The ionic radius of a cobalt ion is greater than its
atomic radius.
(d) Breaking an ionic bond between cobalt and sulfur
requires energy.
28. Which of the following statements are false regarding an
ionic bond between aluminum and nitrogen in an AlN formula unit?
(a) Aluminum and nitride ions bond by covalent attraction.
(b) Aluminum atoms lose electrons and nitrogen atoms
gain electrons.
(c) The ionic radius of an aluminum ion is less than its
atomic radius.
(d) Breaking an ionic bond between aluminum and nitrogen releases energy.
Covalent Bonds (Sec. 12.3)
29. Which of the following is less?
(a) the sum of the Hand Cl atomic radii, or the bond length
inH-Cl
(b) the sum of the 0 and 0 atomic radii, or the bond length
inO=O
30. Which of the following is less?
(a) the sum of the H and Br atomic radii, or the bond length
inH-Br
(b) the sum of the Sand 0 atomic radii, or the bond length
inS=O
31. Which of the following statements are false regarding a
covalent bond between carbon and oxygen atoms in a carbon monoxide, CO, molecule?
(a) Valence electrons are transferred from carbon to
oxygen atoms.
(b) Bonding electrons are distributed over the entire
CO molecule.
(c) The bond length is less than the sum of the two
atomic radii.
(d) Energy is released when a covalent bond is broken.
32. Which of the following statements are false regarding a
covalent bond between nitrogen and oxygen atoms in a
nitric oxide, NO, molecule?
(a) Valence electrons are shared between nitrogen and oxygen atoms.
(b) Bonding electrons are found only between the
bonded atoms.
(c) The bond length is greater than the sum of the two
atomic radii.
(d) Energy is released when a covalent bond is formed.
Electron Dot Formulas of Molecules (Sec. 12.4)
'.\:). Write the electron dot formula and draw the structural
formula for each of the following molecules. (The central
atom is indicated in bold.)
(a) H2
(c) HBr
(b) F2
(d) NH3
34. Write the electron dot formula and draw the structural
formula for each of the following molecules:
(a) Cl2
(b) 02
(c) HI
(d) PH3
Write the electron dot formula and draw the structural
formula for each of the following molecules:
(a) HONO
(b) 502
(c) C2H4
(d) C2H2
36. Write the electron dot formula and draw the structural
formula for each of the following molecules:
(a) N2
(b) Pl3
(c) CS2
(d) HOCl
. Write the electron dot formula and draw the structural
formula for each of the following molecules:
(a) CH4
(b) OF2
(c) H202
(d) NF3
38. Write the electron dot formula and draw the structural
formula for each of the following molecules:
(a) CCl4
(b) HON02
(c) CH30H
(d) HOCN
EXERCISES
Write the electron dot formula and draw the structural formula for each of the following polyatomic ions. (Central
aton1s are indicated in bold.)
(a) Bro··
(b) Br02 (c) Br03 ·(d) Br04 -
351
54. Refer to Figure 12.9 and label each atom in the following
polar covalent bonds using delta notation:
(a) C--H
(b) Se-0
(c) P-1
(d) H-Br
1
O. 'vVrite the electron dot formula and draw the structural formula for each of the following polyatomic ions:
(a) 10(b) I02 (c) I0 3 (d) 104 -
Refer to Figure 12.9 and indicate which of the following are
nonpolar covalent bonds:
(a) Cl-Cl
(b) Cl-N
(c) N-H
(d) H-P
Write the electron dot formula and draw the structural formula for each of the following polyatomic ions:
(b) HS04 (a) 5042(d) HS03 (c) 503 2-
56. Refer to Figure 12.9 and indicate which of the following are
nonpolar covalent bonds:
(a) 1-C
(b) C-S
(c) S-H
(d) H-Br
Which of the following elements occur naturally as
diatomic molecules: H, N, Cl, Br, Ar?
58. Which of the following elements occur naturally as
diatomic molecules: He, 0, F, T, Ne?
4'.:. Write the electron dot formula and draw the structural for-
mula for each of the following polyatomic ions:
(b) HP04 2 (a) P04 :i3
(c) P0 3 (d) HP03 2Write the electron dot formula and draw the structural formula for each of the following polyatomic ions:
(a) H3o+
(b) OH(c) HS
(d) CN-
1
44 Write the electron dot formula and draw the structural for-
mula for each of the following polyatomic ions:
(b) Seo., 2(a) PH 4 +
lc) co., 2(d) B03 3-
46.
48.
50.
32.
\Vhat is the general trend in electronegativity within a
c,roup of elements in the periodic table?
/\That is the general trend in electronegativity within a
1eriod of elements in the periodic table?
"ihich elements are more electronegative: metals
nonmetals?
·Jhich elements are more electronegative: semimetals
nonmetals?
"edict which element in each of the following pairs is
· ore electronegative according to the general trends in the
eriodic table:
Br or Cl
(b) 0 or S
(d) Nor F
Se or As
•vdict which element in each of the following pairs is
.ore electronegative according to the general trends in the
-riodic table:
(b) C or B
Se or Br
(d) Ba or Be
Te or S
··fer to the values in Figure 12.9 and calculate the elec:>negativity difference for each of the following bonds:
Br-Cl
(b) Br-F
1-Cl
(d) I-Br
r •fer to the values in Figure 12.9 and calculate the elect 'negativity difference for each of the following bonds:
H-Cl
(b) H-Br
N-0
(d)C-0
F fer to Figure 12.9 and label each atom in the following
t .ar covalent bonds using delta notation (o+ and o ):
( H-S
(b) 0-S
(c N-F
(d) S-Cl
60.
62.
64.
66.
An oxygen atom can bond to a hydrogen bromide molecule
to give HBrO. Draw the electron dot formula for HBrO and
label a coordinate covalent bond.
An oxygen atom can bond to a hydrogen iodide molecule to
give HIO. Draw the electron dot formula for HIO and label
a coordinate covalent bond.
An oxygen atom can bond to a HBrO molecule to give
HBr0 2. Draw the electron dot formula for HBr02 and label
a coordinate covalent bond.
An oxygen atom can bond to a HIO molecule to give HI02.
Draw the electron dot formula for HI0 2 and label a coordinate covalent bond.
A hydrogen ion can bond to an ammonia molecule, NH3,
forming NH 4+. Draw the electron dot formula for NH4 +
and label a coordinate covalent bond.
A hydrogen ion can bond to a phosphine molecule, PH 3 ,
forming PH4+. Draw the electron dot formula for PH4.,.
and label a coordinate covalent bond.
A nitrite ion, N0 2 - , can bond to an oxygen atom to form
the nitrate ion. Draw the electron dot formula for N03 and label a coordinate covalent bond.
A phosphite ion, P03 3 -, can bond to an oxygen atom to
form the phosphate ion. Draw the electron dot formula for
PG13 - and label a coordinate covalent bond.
1
Diagram a hydrogen bond between two molecules of
ammonia, NH3.
68. Diagram a hydrogen bond between two molecules of
hydrogen fluoride, HF.
Which is greater, the energy to break a hydrogen bond or a
polar covalent bond?
70. Which is longer, the length of a hydrogen bond or a polar
covalent bond?
352
CHAPTER 12 CHEMICAL BONDING
Shapes of Molecules (Sec. 12.10)
n.
72.
73.
74.
7S.
76.
77.
78.
Predict the electron pair geometry, the molecular shape,
and the bond angle for a silane molecule, SiH4, using
VSEPR theory.
Predict the electron pair geometry, the molecular shape, and
the bond angle for a carbon tetrabromide molecule, CBr4,
using VSEPR theory.
Predict the electron pair geometry, the molecular shape, and
the bond angle for a nitrogen triiodide molecule, NI3, using
VSEPR theory.
Predict the electron pair geometry, the molecular shape, and
the bond angle for a phosphine molecule, PH3, using
VSEPR theory.
Predict the electron pair geometry, the molecular shape, and
the bond angle for a hydrogen sulfide molecule, H 2S, using
VSEPR theory.
Predict the electron pair geometry, the molecular shape, and
the bbnd angle for a dichlorine monoxide molecule, Cl20,
using VSEPR theory.
Apply VSEPR theory t~ explain why CF4 is a nonpolar molecule even though it has four polar bonds.
Apply VSEPR theory to explain why C02 is a nonpolar
molecule even though it has two polar bonds.
84.
86.
88.
90.
YL
92.
94.
General Exercises
79. State whether the representative particle in each of the fol-
lowing substances is an atom, a molecule, or a formula unit:
(a) uranium, U
(b) fluorine, F2
(c) uranium hexafluoride, UF 6
(d) hydrogen fluoride, HF
80. State whether the representative particle in each of the following substances is an atom, a molecule, or a formula unit:
(a) plutonium, Pu
(b) oxygen, 02
(c) plutonium(III) oxide, Pu203
(d) hydrogen peroxide, H202
s i. Write formula units by combining the cations and anions in
each of the following pairs:
(a) Sr 2+ and As 3 (b) Ra2+ and 0 2(c) Al 3 + and C0 3 2(d) Cd2+ and OH82. Write formula units by combining the cations and anions in
each of the following pairs:
(b) Ti4+ and 0 2(a) Sc3 + and N 3 (d) Hg22+ and P043 (c) NH4 +and C03 2-
12
1;5.
96.
98.
9'J
100.
Explain why the radius of a sodium ion (0.095 nm) is
about half that of a sodium atom (0.186 nm).
Explain why the radius of a chloride ion (0.181 nm) is
about twice that of a chlorine atom (0.099 nm).
Refer to the values in Figure 12.9 and calculate the electronegativity difference in a B-Cl bond.
Refer to the values in Figure 12.9 and calculate the electronegativity difference in a Sb-Cl bond.
Refer to the values in Figure 12.9 and calculate the electronegativity difference in a H-P bond.
Refer to the values in Figure 12.9 and calculate the electronegativity difference in a S-1 bond.
Label the polar Ge-Cl bond using delta notation (8+
and 8-).
Label the polar As-Cl bond using delta notation (8+
and 8-).
Write the electron dot formula and draw the structural formula for silane, SiH4, whose central atom is a semimetal.
Write the electron dot formula and draw the structural formula for stibine, SbH3, whose central atom is a semimetal.
Write the electron dot formula and draw the structural
formula for the arsenate ion, As03 3 -, whose central
atom is a semimetal.
Write the electron dot formula and draw the structural
formula for the silicate ion, Si03 2-, whose central atom
is a semimetal.
Predict the electron pair geometry, the molecular shape,
and the bond angle for a carbon disulfide molecule, CS2,
using VSEPR theory.
Predict the electron pair geometry, the molecular shape,
and the bond angle for a silicon dioxide molecule, Si02,
using VSEPR theory.
Predict the electron pair geometry, the molecular shape,
and the bond angle for a phosgene molecule, CC120,
using VSEPR theory.
Predict the electron pair geometry, the molecular shape,
and the bond angle for a carbonate ion, co/-' using
VSEPR theory.
Xenon dioxide is a slightly stable molecule that contains a
noble gas. Write the electron dot formula and draw the
structural formula for Xe0 2.
Xenon trioxide is a slightly stable molecule that contains a
noble gas. Write the electron dot formula and draw the
structural formula for Xe03 .
Chapter Self-Test
1. Predict which of the following has a covalent bond.
(Sec. 12.1)
(a) Cao
(b) Coo
(c) CO
(d) all of the above
(e) none of the above
Answers to Self-Test are in Appendix J.
2. Which of the following statements is true regarding an ioni
bond between calcium and oxygen in a CaO formula unit?
(Sec. 12.2)
(a) Calcium atoms lose electrons and oxygen atoms
gain electrons.