Deck 7: Covalent Bonds and Molecular Structure

Question 1

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

Answer 1

intermolecular,lower

Question 2

Covalent bonding is a

A)gain of electrons.
B)loss of electrons.
C)transfer of electrons.
D)sharing of electrons.

Answer 2

sharing of electrons.

Question 3

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.

Answer 3

should result in the release of 243 kJ per mole of Cl₂ formed.

Question 4

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.

Question 5

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.

Question 6

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.

Question 7

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.

Question 8

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.

Question 9

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.

Question 10

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.

Question 11

Which molecule contains the most polar bonds?

A)CF₄
B)CO₂
C)CN^-
D)CH₄

Question 12

Of the following elements,which has the highest electronegativity?

A)P
B)S
C)Sc
D)As

Question 13

Which molecule contains the most easily broken carbon-carbon bond?

A)H₃C-CH₃
B)H₂C=CH₂
C)F₂C=CF₂
D)HCCH

Question 14

Which bond should have the highest bond dissociation energy?

A)N-N
B)NN
C)N=N
D)All three bonds should have about the same dissociation energy.

Question 15

Which is the longest bond?

A)N-N
B)NN
C)N=N
D)All three bond lengths should be about the same.

Question 16

Which molecule has the weakest bonds?

A)CF₄
B)CCl₄
C)CBr₄
D)CI₄

Question 17

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.

Question 18

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

Question 19

Of the following elements,which has the lowest electronegativity?

A)Mg
B)Cl
C)Ca
D)Br

Question 20

Which compound is most likely to exist as a gas at room temperature?

A)Al₄C₃
B)CF₄
C)CaF₂
D)WC

Question 21

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

Question 22

Which molecule contains a triple bond?

A)F₂
B)O₃
C)HCN
D)H₂CO

Question 23

How many electrons are in the valence shell of I in IF₄^-?

A)8
B)10
C)12
D)14

Question 24

Which is the most acceptable electron dot structure for N₂H₂?

A)
B)
C) H - N =N - H
D)

Question 25

Identify the fourth-row element X that forms the ion.

A)Ge
B)As
C)Se
D)Kr

Question 26

How many lone pairs of electrons are on the P atom in PF₃?

A)0
B)1
C)2
D)3

Question 27

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.

Question 28

A::A represents

A)a double bond.
B)a quadruple bond.
C)one lone pair of electrons.
D)two lone pairs of electrons.

Question 29

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

Question 30

Elements that can accommodate more than eight electrons in their valence shell occur only in periodic table period

A)2 or lower.
B)3 or lower.
C)4 or lower.
D)5 or lower.

Question 31

How many of the σ bonds in H₂SO₄ are coordinate covalent bonds?

A)0
B)2
C)4
D)6

Question 32

Which of the following contains an atom that does not obey the octet rule?

A)KBr
B)CO₂
C)ClF₃
D)ICl

Question 33

The nitrogen-nitrogen bond in :N=N: has a bond order of

A)3
B)1
C)2
D)6

Question 34

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.

Question 35

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.

Question 36

A chlorine atom in Cl₂ should have a

A)charge of 1-.
B)partial charge δ-.
C)partial charge δ+.
D)charge of 0.

Question 37

Which element can accommodate more than eight electrons in its valence shell?

A)C
B)O
C)P
D)He

Question 38

How many lone pairs of electrons are on the Xe atom in XeF₆?

A)0
B)1
C)2
D)3

Question 39

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

Question 40

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.

Question 41

A molecular compound that obeys the octet rule in which all atoms have a zero formal charge is

A)BaCl₂
B)BrF₃
C)NCl₃
D)XeF₄

Question 42

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.

Question 43

Two resonance forms for SOCl₂ are given below.
Which is favored by the octet rule and which by formal charge considerations?

A)I is favored by the octet rule and by formal charge considerations.
B)I is favored by the octet rule and II by formal charge considerations.
C)II is favored by the octet rule and I by formal charge considerations.
D)II is favored by the octet rule and by formal charge considerations.

Question 44

Assign formal charges to each atom in the resonance form for SOCl₂ given below.

A)0 for Cl,0 for S,and 0 for O
B)0 for Cl,+1 for S,and -1 for O
C)-1 for Cl,+4 for S,and -2 for O
D)-1 for Cl,-2 for S,and -2 for O

Question 45

How many double and single bonds are in the resonance form for SO₂ in which the formal charges on each atom are zero?

A)two single bonds and no double bonds
B)one single bond and one double bond
C)no single bonds and two double bonds
D)Each of these is possible.

Question 46

Assign formal charges to each atom in the resonance form for SOCl₂ given below.

A)0 for Cl,0 for S,and 0 for O
B)0 for Cl,+1 for S,and -1 for O
C)-1 for Cl,+4 for S,and -2 for O
D)-1 for Cl,-2 for S,and -2 for O

Question 47

Assign formal charges to all atoms in the following resonance form for HNO₃.

A)0 for all atoms
B)+1 for N,-1 for oxygen (c),0 for all other atoms
C)+1 for N and H,-1 for oxygen (a)and oxygen (c),0 for oxygen (b)
D)+1 for H,-2 for each oxygen,+5 for N

Question 48

What geometric arrangement of charge clouds is expected for an atom that has five charge clouds?

A)tetrahedral
B)square planar
C)trigonal bipyramidal
D)octahedral

Question 49

Which of the following should be nonplanar?

A)only I
B)only II
C)only III
D)I and III

Question 50

In the best Lewis structure for NO⁺,what is the formal charge on the N atom?

A)-1
B)0
C)+1
D)+2

Question 51

Which of the following are allowed resonance forms of NCS^-?

A)only I
B)only II
C)only III
D)I and III

Question 52

Which is expected to have the strongest C-O bond?

A)CH₃OH
B)COCl₂
C)CH₃CO₂^-
D)CO₃^2-

Question 53

How many lone pairs are on the Br atom in BrF₂^-?

A)0
B)1
C)2
D)3

Question 54

Which electron dot structure for OCN^- has a formal charge of -1 on the most electronegative atom?

A)
B)
C)
D)

Question 55

What is the approximate carbon-oxygen bond order in CO₃^2-?

A)1
B)4/3
C)5/3
D)2

Question 56

Based on formal charge considerations,the electron-dot structure of CO₃^2- ion has

A)two resonance structures involving two single bonds and one double bond.
B)two resonance structures involving one single bond and two double bonds.
C)three resonance structures involving two single bonds and one double bond.
D)three resonance structures involving one single bond and two double bonds.

Question 57

Based on VSEPR theory,which should have the smallest XAX bond angle?

A)
B)
C)
D)

Question 58

Based on formal charges,what is the S-O bond order in SO₄^2-?

A)1
B)1)3
C)1)5
D)2

Question 59

Which one of the following is expected to exhibit resonance?

A)NH₄⁺
B)HCN
C)CO₂
D)NO₂^-

Question 60

How many resonance structures are required in the electron-dot structure of CO₃^2-?

A)two
B)three
C)four
D)five

Question 61

The VSEPR model predicts the O-O-O bond angle in O₃ to be

A)90°.
B)109.5°.
C)less than 120° but greater than 109.5°.
D)120°.

Question 62

A single sp³ hybrid orbital has

A)one lobe.
B)two lobes of equal size.
C)two lobes of unequal size.
D)four lobes of equal size.

Question 63

What orbital hybridization is expected for the central atom in a molecule with a trigonal planar geometry?

A)sp
B)sp²
C)sp³
D)None of these

Question 64

Arrange in order from the smallest to the largest bond angle: CH₃⁺,NF₃,NH₄⁺,XeF₄.

A)CH₃⁺,NF₃,NH₄⁺,XeF₄
B)NF₃,NH₄⁺,XeF₄,CH₃⁺
C)XeF₄,NH₄⁺,NF₃,CH₃⁺
D)XeF₄,NF₃,NH₄⁺,CH₃⁺

Question 65

Which of the following best describes ICl₂^-? It has a molecular geometry that is

A)linear molecular shape with no lone pairs on the I atom.
B)linear molecular shape with lone pairs on the I atom.
C)non-linear molecular shape with no lone pairs on the I atom.
D)non-linear molecular shape with lone pairs on the I atom.

Question 66

What is the smallest bond angle in SF₆?

A)60°
B)90°
C)109.5°
D)120°

Question 67

The orbital hybridization on the carbon atom in HCN is

A)sp.
B)sp².
C)sp³.
D)None of these

Question 68

Which of the following would be expected to have sp² hybridization on atom A?

A)II
B)I and III
C)I,II,and III
D)I and IV

Question 69

Which of the following is not true?

A)The sp³ hybrid orbitals are degenerate.
B)An sp³ hybrid orbital may hold a lone pair of electrons.
C)An sp³ hybrid orbital may form a sigma bond by overlap with an orbital on another atom.
D)An sp³ hybrid orbital may form a pi bond by overlap with an orbital on another atom.

Question 70

What is the molecular geometry of BrF₄^-?

A)seesaw
B)square planar
C)square pyramidal
D)tetrahedral

Question 71

The number of sp² hybrid orbitals on the carbon atom in CO₃^2- is

A)one.
B)two.
C)three.
D)four.

Question 72

What is the molecular geometry of AsCl₃?

A)T-shaped
B)tetrahedral
C)trigonal planar
D)trigonal pyramidal

Question 73

Which of the following is not a valence bond concept?

A)The greater the overlap between the orbitals on two atoms,the stronger the bond.
B)Lone pair electrons are in atomic orbitals or in hybrid atomic orbitals.
C)Atomic orbitals on two atoms may overlap to form antibonding orbitals.
D)A pair of electrons in a bond is shared by both atoms.

Question 74

Which orbital hybridization is associated with a tetrahedral charge cloud arrangement?

A)sp
B)sp²
C)sp³
D)None of these

Question 75

What is the O-N-O bond angle in NO₃^-?

A)less than 109.5°
B)109.5°
C)120°
D)greater than 120°

Question 76

What is the molecular geometry of IF₅?

A)octahedral
B)seesaw
C)square pyramidal
D)trigonal bipyramidal

Question 77

Which of the following should be nonlinear?

A)only I
B)only II
C)only III
D)II and III

Question 78

What is the angle between adjacent sp³ hybrid orbitals?

A)90°
B)109.5°
C)120°
D)180°

Question 79

A triple bond is generally composed of

A)three π bonds.
B)two π bonds and one σ bond.
C)one π bond and two σ bonds.
D)three σ bonds.

Question 80

What is the molecular geometry of TeCl₄?

A)seesaw
B)square planar
C)square pyramidal
D)tetrahedral