CHE 1401 - Summer 2013 - Chapter 8
Homework 8 (Chapter 8: Basic concepts of chemical bonding)
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MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the
question.
1) In the nitrite ion (NO2-), __________.
A) both bonds are single bonds
B) both bonds are double bonds
C) one bond is a double bond and the other is a single bond
D) there are 20 valence electrons
E) both bonds are the same
1)
2) In the Lewis symbol for a sulfur atom, there are __________ paired and
__________ unpaired electrons.
A) 0, 6
B) 2, 2
C) 2, 4
D) 4, 2
E) 5, 1
2)
For the questions that follow, consider the BEST Lewis structures of the following oxyanions:
(i) NO2- (ii) NO3- (iii) SO32- (iv)SO42- (v) BrO33) There can be four equivalent best resonance structures of __________.
A) (i)
B) (ii)
C) (iii)
D) (iv)
E) (v)
3)
4) In which of the ions do all X-O bonds (X indicates the central atom) have the
same length?
A) none
B) all
C) (i) and (ii)
D) (iii) and (v)
E) (iii), (iv), and (v)
4)
5) A valid Lewis structure of __________ cannot be drawn without violating the
octet rule.
A) SeF4
B) PO43C) CF4
D) SiF4
E) NF3
5)
6) Which atom can accommodate an octet of electrons, but doesn't necessarily
have to accommodate an octet?
A) B
B) C
C) O
D) H
E) N
6)
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7) Which of the following has the bonds correctly arranged in order of increasing
polarity?
A) MgF, BeF, NF, OF
B) NF, BeF, MgF, OF
C) OF, NF, BeF, MgF
D) OF, BeF, MgF, NF
E) BeF, MgF, NF, OF
7)
8) As the number of covalent bonds between two atoms increases, the distance
between the atoms __________ and the strength of the bond between them
__________.
A) increases, increases
B) decreases, decreases
C) increases, decreases
D) decreases, increases
E) is unpredictable
8)
9) A valid Lewis structure of __________ cannot be drawn without violating the
octet rule.
A) PCl3
B) CCl4
C) SO3
D) CO2
E) ClF3
9)
10) Of the ions below, only __________ has a noble gas electron configuration.
A) O2+
B) S3C) I+
D) KE) Cl-
10)
11) The electron configuration [Kr]4d 10 represents __________.
A) Sn+2
B) Ag+1
C) Sr+2
D) Rb +1
11)
12) Of the bonds below, __________ is the least polar.
A) C, F
B) Na, Cl
C) Na, S
D) Si, Cl
E) Te+2
12)
E) P, S
13) Using the Born-Haber cycle, the ΔHf° of KBr is equal to __________.
A) ΔHf°[K (g)] + ΔHf°[Br (g)] - I1 - E(Br) + ΔHlattice
B) ΔHf°[K (g)] + ΔHf°[Br (g)] + I1(K) + E(Br) + ΔHlattice
C) ΔHf°[K (g)] - ΔHf°[Br (g)] + I1(K) - E(Br) + ΔHlattice
13)
D) ΔHf°[K (g)] + ΔHf°[Br (g)] + I1(K) + E(Br) - ΔHlattice
E) ΔHf°[K (g)] - ΔHf°[Br (g)] - I1(K) - E(Br) - ΔHlattice
14) Based on the octet rule, boron will most likely form a __________ ion.
A) B2+
B) B3C) B3+
D) B2E) B1+
2
14)
15) Of the following, __________ cannot accommodate more than an octet of
electrons.
A) I
B) As
C) S
D) P
E) O
15)
16) The Lewis structure of the CO32- ion is __________.
A)
16)
B)
C)
D)
E)
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17) Which two bonds are most similar in polarity?
A) ClCl and BeCl
B) IBr and SiCl
C) OF and ClF
D) AlCl and IBr
E) BF and ClF
17)
18) Which of the following names is/are correct for the compound SnCl4?
A) tin tetrachloride and tin (IV) chloride
B) tin (IV) tetrachloride
C) tin (II) chloride and tin (IV) chloride
D) tin chloride and tin (II) tetrachloride
E) tin chloride
18)
19) Which of the following has eight valence electrons?
A) Na+
B) Kr
C) Cl-
19)
D) Ti4+
E) all of the above
20) Of the molecules below, the bond in __________ is the most polar.
A) HI
B) H2
C) HCl
D) HF
20)
E) HBr
21) Dynamite consists of nitroglycerine mixed with __________.
A) solid carbon
B) damp KOH
C) diatomaceous earth or cellulose
D) potassium nitrate
E) TNT
21)
22) Given that the average bond energies for C-H and C-Br bonds are 413 and 276
kJ/mol, respectively, the heat of atomization of bromoform (CHBr3) is
22)
__________ kJ/mol.
A) 689
B) -689
C) 1241
23) Bond enthalpy is __________.
A) always zero
B) sometimes positive, sometimes negative
C) always positive
D) always negative
E) unpredictable
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D) -1378
E) 1378
23)
24) Resonance structures differ by __________.
A) number of atoms only
B) number of electrons only
C) placement of atoms only
D) number and placement of electrons
E) placement of electrons only
24)
25) For resonance forms of a molecule or ion, __________.
A) the same atoms need not be bonded to each other in all resonance forms
B) the observed structure is an average of the resonance forms
C) there cannot be more than two resonance structures for a given species
D) all the resonance structures are observed in various proportions
E) one always corresponds to the observed structure
25)
26) Of the atoms below, __________ is the least electronegative.
A) F
B) Ca
C) Cl
D) Si
26)
27) Of the atoms below, __________ is the most electronegative.
A) Cl
B) Br
C) O
D) F
28) The oxidation number of phosphorus in PF3 is __________.
A) -3
B) +3
C) -2
D) +2
E) Rb
27)
E) N
28)
E) +1
29) The chloride of which of the following metals should have the greatest lattice
energy?
A) potassium
B) sodium
C) cesium
D) rubidium
E) lithium
29)
30) A valid Lewis structure of __________ cannot be drawn without violating the
octet rule.
A) BeH2
B) NF3
C) SO32D) SO2
E) CF4
30)
31) Which of the following does not have eight valence electrons?
A) ClB) Ti+4
C) Sr+1
D) Rb +1
31)
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E) Xe
32) Of the possible bonds between carbon atoms (single, double, and triple),
__________.
A) a single bond is stronger than a double bond
B) a triple bond is longer than a single bond
C) a double bond is stronger than a triple bond
D) a single bond is stronger than a triple bond
E) a double bond is longer than a triple bond
32)
33) The type of compound that is most likely to contain a covalent bond is
__________.
A) held together by the electrostatic forces between oppositely charged ions
B) one that is composed of only nonmetals
C) a solid metal
D) one that is composed of a metal from the far left of the periodic table and a
nonmetal from the far right of the periodic table
E) There is no general rule to predict covalency in bonds.
33)
34) In ionic bond formation, the lattice energy of ions ________ as the magnitude of
the ion charges _______ and the radii __________.
A) increases, decrease, decrease
B) increases, decrease, increase
C) increases, increase, decrease
D) increases, increase, increase
E) decreases, increase, increase
34)
35) The central atom in __________ does not violate the octet rule.
A) ICl4B) CF4
C) XeF4
D) SF4
35)
E) KrF2
36) A valid Lewis structure of __________ cannot be drawn without violating the
octet rule.
A) ICl5
B) SiF4
C) NI3
D) SO 2
E) CO 2
36)
37) Why don't we draw double bonds between the Be atom and the Cl atoms
in BeCl2?
A) That would result in the formal charges not adding up to zero.
B) That would give positive formal charges to the chlorine atoms and a
negative formal charge to the beryllium atom.
C) That would result in more than eight electrons around beryllium.
D) There aren't enough electrons.
E) That would result in more than eight electrons around each chlorine atom.
37)
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38) Most explosives are compounds that decompose rapidly to produce __________
products and a great deal of __________.
A) liquid, heat
B) solid, gas
C) soluble, heat
D) gaseous, heat
E) gaseous, gases
38)
39) Which of the following names is/are correct for the compound TiO2?
A) titanium (IV) dioxide
B) titanium oxide
C) titanium dioxide and titanium (IV) oxide
D) titanium (II) oxide
E) titanium oxide and titanium (IV) dioxide
39)
40) The Lewis structure of N2H2 shows __________.
A) each nitrogen has two nonbonding electron pairs
B) each nitrogen has one nonbonding electron pair
C) a nitrogen-nitrogen triple bond
D) a nitrogen-nitrogen single bond
E) each hydrogen has one nonbonding electron pair
40)
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