Chemistry: The Central Science, 12e (Brown et al.)
Chapter 8 Basic Concepts of Chemical Bonding
8.1 Multiple–Choice Questions
1) Which ion below has a noble gas electron configuration?
A) Li2+
B) Be2+
C) B2+
D) C2+
E) N2-
2) Of the ions below, only __________ has a noble gas electron configuration.
A) S3-
B) O2+
C) I+
D) K–
E) Cl–
3) Which of the following has eight valence electrons?
A) Ti4+
B) Kr
C) Cl–
D) Na+
E) all of the above
4) Which of the following does not have eight valence electrons?
A) Ca+
B) Rb+
C) Xe
D) Br–
E) All of the above have eight valence electrons.
5) Lattice energy is __________.
A) the energy required to convert a mole of ionic solid into its constituent ions in the gas phase
B) the energy given off when gaseous ions combine to form one mole of an ionic solid
C) the energy required to produce one mole of an ionic compound from its constituent elements in their
standard states
D) the sum of ionization energies of the components in an ionic solid
E) the sum of electron affinities of the components in an ionic solid
6) In ionic bond formation, the lattice energy of ions ________ as the magnitude of the ion charges
_______ and the radii __________.
A) increases, decrease, increase
B) increases, increase, increase
C) decreases, increase, increase
D) increases, increase, decrease
E) increases, decrease, decrease
The diagram below is the Born-Huber cycle for the formation of crystalline potassium fluoride.
7) Which energy change corresponds to the electron affinity of fluorine?
A) 2
B) 5
C) 4
D) 1
E) 6
8) Which energy change corresponds to the first ionization energy of potassium?
A) 2
B) 5
C) 4
D) 3
E) 6
9) The electron configuration [Kr]4d10 represents __________.
A) Sr+2
B) Sn+2
C) Te+2
D) Ag+1
E) Rb+1
10) Fe+2 ions are represented by __________.
A) [Ar]3d1
B) [Ar]3d4
C) [Ar]3d6
D) [Ar]3d104s1
E) [Ar]3d3
11) Using the Born-Haber cycle, the ΔHf° of KBr is equal to __________.
A) ΔHf°[K (g)] + ΔHf°[Br (g)] + Il(K) + E(Br) + ΔHlattice
B) ΔHf°[K (g)] – ΔHf°[Br (g)] – Il(K) – E(Br) – ΔHlattice
C) ΔHf°[K (g)] – ΔHf°[Br (g)] + Il(K) – E(Br) + ΔHlattice
D) ΔHf°[K (g)] + ΔHf°[Br (g)] – Il – E(Br) + ΔHlattice
E) ΔHf°[K (g)] + ΔHf°[Br (g)] + Il(K) + E(Br) – ΔHlattice
12) The type of compound that is most likely to contain a covalent bond is __________.
A) 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
B) a solid metal
C) one that is composed of only nonmetals
D) held together by the electrostatic forces between oppositely charged ions
E) There is no general rule to predict covalency in bonds.
13) In which of the molecules below is the carbon-carbon distance the shortest?
A) H2CCH2
B) H–C≡C–H
C) H3C–CH3
D) H2CC CH2
E) H3C–CH2–C H3
14) Of the atoms below, __________ is the most electronegative.
A) Si
B) Cl
C) Rb
D) Ca
E) S
15) Of the molecules below, the bond in __________ is the most polar.
A) HBr
B) HI
C) HCl
D) HF
E) H2
16) Which of the following has the bonds correctly arranged in order of increasing polarity?
A) Be F, Mg F, N F, O F
B) O F, N F, Be F, Mg F
C) O F, Be F, Mg F, N F
D) N F, Be F, Mg F, O F
E) Mg F, Be F, N F, O F
17) The bond length in an HI molecule is 1.61 Å and the measured dipole moment is 0.44 D. What is
the magnitude (in units of e) of the negative charge on I in HI?
(1 debye = 3.34 × 10-30 coulomb-meters; e=1.6 × 10-19 coulombs)
A) 1.6 × 10-19
B) 0.057
C) 9.1
D) 1
E) 0.22
18) The Lewis structure of N2H2 shows __________.
A) a nitrogen-nitrogen triple bond
B) a nitrogen-nitrogen single bond
C) each nitrogen has one nonbonding electron pair
D) each nitrogen has two nonbonding electron pairs
E) each hydrogen has one nonbonding electron pair
19) There are __________ valence electrons in the Lewis structure of CH3CH2Cl.
A) 14
B) 12
C) 18
D) 20
E) 10
20) There are __________ valence electrons in the Lewis structure of CH3OCH2CH3.
A) 18
B) 20
C) 26
D) 32
E) 36
21) In the Lewis symbol for a sulfur atom, there are __________ paired and __________ unpaired
electrons.
A) 2, 2
B) 4, 2
C) 2, 4
D) 0, 6
E) 5, 1
22) The Lewis structure of the COH32– ion is __________.
A)
B)
C)
D)
E)
23) 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) both bonds are the same
E) there are 20 valence electrons
24) Resonance structures differ by __________.
A) number and placement of electrons
B) number of electrons only
C) placement of atoms only
D) number of atoms only
E) placement of electrons only
25) The oxidation number of phosphorus in PF3 is __________.
A) -2
B) +1
C) +3
D) +2
E) -3
26) The oxidation number of iron in Fe2O3 is __________.
A) -2
B) +1
C) +3
D) +2
E) -3
27) To convert from one resonance structure to another, __________.
A) only atoms can be moved
B) electrons and atoms can both be moved
C) only electrons can be moved
D) neither electrons nor atoms can be moved
E) electrons must be added
28) For resonance forms of a molecule or ion, __________.
A) one always corresponds to the observed structure
B) all the resonance structures are observed in various proportions
C) the observed structure is an average of the resonance forms
D) the same atoms need not be bonded to each other in all resonance forms
E) there cannot be more than two resonance structures for a given species
For the questions that follow, consider the BEST Lewis structures of the following oxyanions:
(i) NO2– (ii) NO3– (iii) SO32– (iv) SO42– (v) BrO3–
29) There can be four equivalent best resonance structures of __________.
A) (i)
B) (ii)
C) (iii)
D) (iv)
E) (v)
30) 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)
31) A valid Lewis structure of __________ cannot be drawn without violating the octet rule.
A) NF3
B) IF3
C) PF3
D) SbF3
E) SO42–
32) Based on the octet rule, boron will most likely form a __________ ion.
A) B3-
B) B1+
C) B3+
D) B2+
E) B2-
33) Which of the following does not have eight valence electrons?
A) Cl–
B) Xe
C) Ti+4
D) Rb+1
E) Sr+1
34) A valid Lewis structure of __________ cannot be drawn without violating the octet rule.
A) PO43–
B) SiF4
C) CF4
D) SeF4
E) NF3
35) The central atom in __________ does not violate the octet rule.
A) SF4
B) KrF2
C) CF4
D) XeF4
E) ICl4–
36) The central atom in __________ violates the octet rule.
A) NH3
B) SeF2
C) BF3
D) AsF3
E) CF4
37) A valid Lewis structure of __________ cannot be drawn without violating the octet rule.
A) ClF3
B) PCl3
C) SO3
D) CCl4
E) CO2
38) A valid Lewis structure of __________ cannot be drawn without violating the octet rule.
A) NI3
B) SO2
C) ICl5
D) SiF4
E) CO2
39) A valid Lewis structure of __________ cannot be drawn without violating the octet rule.
A) NF3
B) BeH2
C) SO2
D) CF4
E) SO32-
40) Why don’t we draw double bonds between the Be atom and the Cl atoms in BeCl2?
A) That would give positive formal charges to the chlorine atoms and a negative formal charge to the
beryllium atom.
B) There aren’t enough electrons.
C) That would result in more than eight electrons around beryllium.
D) That would result in more than eight electrons around each chlorine atom.
E) That would result in the formal charges not adding up to zero.
41) Which atom can accommodate an octet of electrons, but doesn’t necessarily have to accommodate an
octet?
A) N
B) C
C) H
D) O
E) B
42) Bond enthalpy is __________.
A) always positive
B) always negative
C) sometimes positive, sometimes negative
D) always zero
E) unpredictable
43) 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 __________ kJ/mol.
A) 1241
B) 689
C) -689
D) 1378
E) -1378
44) Of the bonds C–C, C C, and C≡C, the C–C bond is __________.
A) strongest/shortest
B) strongest/longest
C) weakest/longest
D) weakest/shortest
E) intermediate in both strength and length
45) Of the bonds C–N, C N, and C≡N, the C–N bond is __________.
A) strongest/shortest
B) strongest/longest
C) weakest/shortest
D) weakest/longest
E) intermediate in both strength and length
46) 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
47) Of the possible bonds between carbon atoms (single, double, and triple), __________.
A) a triple bond is longer than a single bond
B) a double bond is stronger than a triple bond
C) a single bond is stronger than a triple bond
D) a double bond is longer than a triple bond
E) a single bond is stronger than a double bond
48) Most explosives are compounds that decompose rapidly to produce __________ products and a
great deal of __________.
A) gaseous, gases
B) liquid, heat
C) soluble, heat
D) solid, gas
E) gaseous, heat
49) Dynamite consists of nitroglycerine mixed with __________.
A) potassium nitrate
B) damp KOH
C) TNT
D) diatomaceous earth or cellulose
E) solid carbon
50) Dynamite __________.
A) was invented by Alfred Nobel
B) is made of nitroglycerine and an absorbent such as diatomaceous earth
C) is a much safer explosive than pure nitroglycerine
D) is an explosive
E) all of the above
8.2 Bimodal Questions
1) Based on the octet rule, magnesium most likely forms a __________ ion.
A) Mg2+
B) Mg2-
C) Mg6-
D) Mg6+
E) Mg–
2) Based on the octet rule, phosphorus most likely forms a __________ ion.
A) P3+
B) P3-
C) P5+
D) P5-
E) P+
3) Based on the octet rule, aluminum most likely forms an __________ ion.
A) Al3+
B) Al4+
C) Al4-
D) Al+
E) Al–
4) Based on the octet rule, iodine most likely forms an __________ ion.
A) I2+
B) I4+
C) I4-
D) I+
E) I-
5) The electron configuration of the phosphide ion (P3-) is __________.
A) [Ne]3s2
B) [Ne]3s23Pl
C) [Ne]3s23P3
D) [Ne]3P2
E) [Ne]3s23P6
6) The electron configuration of the sulfide ion (S2-) is __________.
A) [Ne]3s2
B) [Ne]3s23Pl
C) [Ne]3s23P4
D) [Ne]3P2
E) [Ne]3s23P6
7) The halogens, alkali metals, and alkaline earth metals have __________ valence electrons,
respectively.
A) 7, 4, and 6
B) 1, 5, and 7
C) 8, 2, and 3
D) 7, 1, and 2
E) 2, 7, and 4
8) The only noble gas without eight valence electrons is __________.
A) Ar
B) Ne
C) He
D) Kr
E) All noble gases have eight valence electrons.
9) Which of the following would have to lose two electrons in order to achieve a noble gas electron
configuration?
O Sr Na Se Br
A) O, Se
B) Sr
C) Na
D) Br
E) Sr, O, Se
10) Which of the following would have to lose three electrons in order to achieve a noble gas electron
configuration?
Si Mg Al Cl P
A) Si, P
B) Al
C) P
D) Cl
E) Mg, Al, P
11) Which of the following would have to gain two electrons in order to achieve a noble gas electron
configuration?
O Sr Na Se Br
A) Br
B) Sr
C) Na
D) O, Se
E) Sr, O, Se
12) For a given arrangement of ions, the lattice energy increases as ionic radius __________ and as ionic
charge __________.
A) decreases, increases
B) increases, decreases
C) increases, increases
D) decreases, decreases
E) This cannot be predicted.
13) For a given arrangement of ions, the lattice energy decreases as ionic radius __________ and as
ionic charge __________.
A) decreases, increases
B) increases, decreases
C) increases, increases
D) decreases, decreases
E) This cannot be predicted.
14) The electron configuration of the S2- ion is __________.
A) [Ar]3s23P6
B) [Ar]3s23P2
C) [Ne]3s23P2
D) [Ne]3s23P6
E) [Kr]3s23P-6
15) The electron configuration of the P3- ion is __________.
A) [Ar]3s23P6
B) [Ar]3s23P2
C) [Ne]3s23P6
D) [Ne]3s23P2
E) [Kr]3s23P-6
16) What species has the electron configuration [Ar]3d2?
A) Mn2+
B) Cr2+
C) V3+
D) Fe3+
E) K+
17
17) What species has the electron configuration [Ar]3d4?
A) Mn2+
B) Cr2+
C) V3+
D) Fe3+
E) K+
18) What is the electron configuration for the Co2+ ion?
A) [Ar]4s13d6
B) [Ar]3d7
C) [Ar]3d5
D) [Ar]4s23d9
E) [Ne]3s23p10
19) What is the electron configuration for the Fe3+ ion?
A) [Ar]4s13d6
B) [Ar]4s03d7
C) [Ar]4s03d5
D) [Ar]4s23d9
E) [Ne]3s23p10
20) What is the electron configuration for the Fe2+ ion?
A) [Ar]4s03d6
B) [Ar]4s23d4
C) [Ar]4s03d8
D) [Ar]4s23d8
E) [Ar]4s63d2