General Chemistry: Atoms First, 2e (McMurry and Fay)
Chapter 4 Atoms and Covalent Bonds
4.1 Multiple Choice Questions
1) Covalent bonding is a
A) gain of electrons.
B) loss of electrons.
C) transfer of electrons.
D) sharing of electrons.
2) Which electrostatic forces hold atoms together in a molecule?
A) electron-electron forces
B) electron-nucleus forces
C) nucleus-nucleus forces
D) all three forces
3) At the equilibrium bond length
A) the attractive forces holding the atoms together are less than the repulsive forces.
B) the potential energy is a maximum.
C) the potential energy is a minimum.
D) the repulsive forces are greater than the attractive forces holding the atoms together.
4) Butyric acid has the structural formula given below.
What is the molecular or chemical formula for butyric acid?
A) CHO
B) C2H4O
C) C4H8O2
D) C5H8O3
5) Which is the longest bond?
A) N–N
B) N=N
C) N N
D) All three bond lengths should be about the same.
6) Which bond should have the highest bond dissociation energy?
A) N–N
B) N N
C) N N
D) All three bonds should have about the same dissociation energy.
7) Which molecule contains the most easily broken carbon-carbon bond?
A) H3C–CH3
B) H2C=CH2
C) F2C=CF2
D) HC CH
8) The Cl–Cl bond energy is 243 kJ/mol. Therefore the formation of a single bond between
chlorine atoms
A) should require the absorption of 243 kJ per mole of Cl2 formed.
B) should require the absorption of 486 kJ per mole of Cl2 formed.
C) should result in the release of 243 kJ per mole of Cl2 formed.
D) should result in the release of 486 kJ per mole of Cl2 formed.
9) In general, at room temperature
A) ionic compounds are all solids and covalent compounds are all gases.
B) ionic compounds are all solids, but covalent compounds may be solids, liquids, or gases.
C) ionic compounds are all solids, and covalent compounds are liquids or gases.
D) covalent compounds are all gases, but ionic compounds may be solids, liquids, or gases.
10) Compound A is a solid with a melting point of 125°C, and compound B is a gas at 25°C and
one atmosphere pressure. Based on these data, one would expect
A) both compounds to be covalent.
B) compound A to be ionic and compound B to be covalent.
C) compound A to be covalent and compound B to be ionic.
D) both compounds to be ionic.
11) When melting S8 ________ forces must be overcome and S8 is expected to have a ________
melting point than MgS.
A) covalent bonding, higher
B) covalent bonding, lower
C) intermolecular, higher
D) intermolecular, lower
12) Of the following elements, which has the highest electronegativity?
A) P
B) S
C) Sc
D) As
13) Of the following elements, which has the lowest electronegativity?
A) Mg
B) Cl
C) Ca
D) Br
14) The electronegativity is 2.1 for H and 1.8 for Si. Based on these electronegativities, SiH4
would be expected to
A) be ionic and contain H– ions.
B) be ionic and contain H+ ions.
C) have polar covalent bonds with a partial negative charges on the H atoms.
D) have polar covalent bonds with a partial positive charges on the H atoms.
15) A reactive element with a relatively high electronegativity would be expected to have a
relatively
A) small negative electron affinity and a relatively low ionization energy.
B) small negative electron affinity and a relatively high ionization energy.
C) large negative electron affinity and a relatively low ionization energy.
D) large negative electron affinity and a relatively high ionization energy.
16) The compound ICl contains
A) ionic bonds.
B) nonpolar covalent bonds.
C) polar covalent bonds, with partial negative charges on the Cl atoms.
D) polar covalent bonds, with partial negative charges on the I atoms.
17) The greater the electronegativity difference between two bonded atoms, the
A) greater the bond order.
B) greater the covalent character of the bond.
C) greater the ionic character of the bond.
D) more unstable the bond.
18) Which molecule contains the most polar bonds?
A) CF4
B) CO2
C) CN–
D) CH4
19) The electronegativity for both sulfur and carbon is 2.5. Therefore the compound CS2 would
be expected to
A) be ionic with C as the anion.
B) be ionic with C as the cation.
C) have nonpolar covalent bonds between C and S.
D) have polar covalent bonds between C and S.
20) The phosphorus atom in PCl3 would be expected to have a
A) partial positive (δ+) charge.
B) partial negative (δ-) charge.
C) 3+ charge.
D) 3- charge.
21) A chlorine atom in Cl2 should have a
A) charge of 1-.
B) partial charge δ-.
C) partial charge δ+.
D) charge of 0.
22) Element A has an electronegativity of 0.8 and element B has an electronegativity of 3.0.
Which statement best describes the bonding in A3B?
A) The AB bond is largely covalent with a δ– on A.
B) The AB bond is largely covalent with a δ+ on A.
C) The compound is largely ionic with A as the cation.
D) The compound is largely ionic with A as the anion.
23) Based on the indicated electronegativities, arrange the following in order of increasing ionic
character: CsBr, LaBr3, PBr3, MgBr2.
A) CsBr, LaBr3, MgBr2, PBr3
B) CsBr, MgBr2, PBr3, LaBr3
C) PBr3, LaBr3, MgBr2, CsBr
D) PBr3, MgBr2, LaBr3, CsBr
24) The electronegativities for the elements vary from 0.7 for cesium to 4.0 for fluorine. The
electronegativity for iodine is 2.5. Based entirely on the general guidelines for electronegativities
and bond character,
A) binary compounds with iodine should all be polar covalent with a δ– on I.
B) binary compounds with iodine should all be polar covalent with a δ+ on I.
C) compounds with iodine may be ionic, polar covalent, or nonpolar covalent.
D) no binary compounds with iodine should be substantially ionic.
25) Arrange the following in order of increasing ionic character: Al2S3, MgS, Na2S, P4S3, S8.
A) MgS, Na2S, Al2S3, P4S3, S8
B) Na2S, MgS, Al2S3, P4S3, S8
C) S8, P4S3, Al2S3, MgS, Na2S
D) S8, P4S3, Al2S3, Na2S, MgS
26) The formula for dinitrogen trioxide is
A) N(OH)3.
B) (NO3)2.
C) N2O3.
D) N3O2.
27) The compound, NO2, is named
A) nitrate.
B) nitrite.
C) nitrogen dioxide.
D) nitrogen(IV) oxide.
28) A::A represents
A) a double bond.
B) a quadruple bond.
C) one lone pair of electrons.
D) two lone pairs of electrons.
29) The nitrogen-nitrogen bond in :N N: has a bond order of
A) 3
B) 1
C) 2
D) 6
30) A coordinate covalent bond may be formed when
A) the central atom donates both electrons in forming a single bond
B) the central atom donates a pair of electrons and the terminal atom donates a pair of electrons
to from a double bond.
C) a covalent bond has a bond order of 1.5.
D) a covalent bond has a bond order of 3.
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31) How many lone pairs of electrons are on the P atom in PF3?
A) 0
B) 1
C) 2
D) 3
32) Which is the most acceptable electron dot structure for N2H2?
A) H –– – H
B) H –=– H
C) H – N N – H
D) H –– H
33) In the most acceptable electron-dot structure for carbonyl fluoride, COF2 the central atom is
A) C, which is singly-bonded to O.
B) C, which is doubly-bonded to O.
C) O, which is singly-bonded to C
D) O, which is doubly-bonded to C.
34) Which molecule contains a triple bond?
A) F2
B) O3
C) HCN
D) H2CO
35) Elements that can accommodate more than eight electrons in their valence shell occur only in
periodic table periods
A) 2 through 7.
B) 3 through 7.
C) 4 through 7.
D) 5 through 7.
36) Which element can accommodate more than eight electrons in its valence shell?
A) C
B) O
C) P
D) He
37) Which of the following contains an atom that does not obey the octet rule?
A) KBr
B) CO2
C) ClF3
D) ICl
38) How many lone pairs of electrons are on the Xe atom in XeF6?
A) 0
B) 1
C) 2
D) 3
39) How many electrons are in the valence shell of I in IF4–?
A) 8
B) 10
C) 12
D) 14
40) Identify the fourth-row element X that forms the ion
A) Ge
B) As
C) Se
D) Kr
41) Draw the Lewis Dot structure for . The number of hydrogen terminal atoms attached
to the central atom is
A) 0
B) 1
C) 2
D) 3
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42) Draw the Lewis Dot structure for B . The number of electrons placed on the central atom
is
A) 6
B) 7
C) 8
D) 4
43) Consider a molecule with the following connections:
When a valid electron dot structure is written, how many double bonds will the molecule
contain?
A) 0
B) 1
C) 2
D) 4
44) How many lone pairs are on the Br atom in BrF2–?
A) 0
B) 1
C) 2
D) 3
45) NO2– is be expected to have
A) two single bonds.
B) one single and one double bond.
C) two double bonds.
D) two identical bonds intermediate between a single and a double bond.
46) How many resonance structures are required in the electron-dot structure of CO32-?