Deck 7: Covalent Bonding and Electron-Dot Structures

Question 1

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.

Answer 1

The compound is largely ionic with A as the cation.

Question 2

A nitrogen atom in N₂ should have a

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

Answer 2

charge of 0.

Question 3

The phosphorus atom in PCl₅ would be expected to have a

A)partial positive (δ+)charge.
B)partial negative (δ-)charge.
C)3+ charge.
D)3- charge.

Answer 3

partial positive (δ+)charge.

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

Which is the longest bond?

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

Question 6

Which of the following bonds is expected to be stronger?

A)C-C bond with a bond order of 0
B)C-C bond with a bond order of 1
C)C-C bond with a bond order of 2
D)C-C bond with a bond order of 3

Question 7

Which molecule has the weakest bonds?

A)CF₄
B)CCl₄
C)CBr₄
D)CI₄

Question 8

Which bond should have the highest bond dissociation energy?

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

Question 9

Of the following elements,which has the lowest electronegativity?

A)Sn
B)As
C)S
D)Tl

Question 10

Covalent bonding is a

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

Question 11

The compound CCl₄ 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 C atoms.

Question 12

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 13

What bond distance is expected to be longest?

A)A carbon-carbon bond with a bond order of 0
B)A carbon-carbon bond with a bond order of 1
C)A carbon-carbon bond with a bond order of 2
D)A carbon-carbon bond with a bond order of 3

Question 14

Of the following elements,which has the highest electronegativity?

A)Si
B)N
C)Ga
D)Cd

Question 15

The electronegativity is 2.1 for H and 3.0 for N.Based on these electronegativities,NH₄⁺ 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 16

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 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.

Question 18

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

A)H₃C-CH₃
B)H₂C=CH₂
C)F₂C=CF₂
D)HC
CH

Question 19

What is the bond order of the O-O bond in O₂?

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

Question 20

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 21

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 22

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

Question 23

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

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

Question 24

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

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

Question 25

A::A represents

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

Question 26

Which is the most acceptable electron dot structure for N₂H₂?

A)H -
-

- H
B)H -
=

- H
C)H - N
N - H
D)H -


- H

Question 27

How many lone pairs are on the Br atom in BrI₂^-?

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

Question 28

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 29

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

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

Question 30

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 31

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 32

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 33

In the electron dot structure of HCN,the bond order of CN is

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

Question 34

How many lone pairs in the correct electron dot structure of O₃?

A)2
B)3
C)4
D)6

Question 35

Which of the following molecules is expected to have the highest melting point?

A)H₂
B)Cl₂
C)CCl₄
D)NaCl

Question 36

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

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

Question 37

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 38

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

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

Question 39

How many lone pairs of electrons are on the I atom in IF₅?

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

Question 40

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 41

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 42

The phosphorus atom in PCl₅ would be expected to have a

A)partial positive (δ+)charge.
B)partial negative (δ-)charge.
C)3+ charge.
D)3- charge.

Question 43

In the best Lewis structure for CO₂,what is the formal charge on the C atom?

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

Question 44

Which molecule contains the most polar bonds?

A)CF₄
B)TeO₂
C)NO^-
D)CCl₄

Question 45

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 46

Of the following elements,which has the lowest electronegativity?

A)Ba
B)I
C)Ra
D)At

Question 47

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

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

Question 48

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 49

The chlorine atom in Cl₂ would be expected to have a

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

Question 50

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

A)[:
= C =

:] ^-
B)[: N
C -

:] ^-
C)[:
- C

O :] ^-
D)[:
- O

C :] ^-

Question 51

The electronegativity is 2.1 for H and 1.9 for Sb.Based on these electronegativities SbH₃ 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 52

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 53

Which of the following are allowed resonance forms of NCS^-? I [: N C - :] ^- and [: = C = :] ^-
II [: N C - :] ^- and [: N C = :] ^-
III [: N C - :] ^- and [: - C N :] ^-

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

Question 54

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 55

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 56

The Cl-Cl bond energy is 199 kJ/mol.Therefore the formation of a single bond between atoms

A)should require the absorption of 199 kJ per mole of Cl-Cl formed.
B)should require the absorption of 398 kJ per mole of Cl-Cl formed.
C)should result in the release of 199 kJ per mole of Cl-Cl formed.
D)should result in the release of 398 kJ per mole of Cl-Cl formed.

Question 57

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 58

Of the following elements,which has the highest electronegativity?

A)As
B)Se
C)Y
D)Sb

Question 59

The electronegativity value of C is 2.5 while the electronegativity value of F is 3.98.What is the expected electronegativity value for the C-F bond?

A)0
B)6.48
C)1.48
D)-1.48

Question 60

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 61

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

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

Question 62

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

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

Question 63

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

A)LiBr
B)CO₂
C)PCl₃
D)CCl₄

Question 64

Among the compounds H₃C-CH₃,H₂C=CH₂,and HC CH,the compound with the strongest carbon-carbon bond is ________,and the compound with the longest carbon-carbon bond is ________.

Question 65

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

A)SrBr₂.
B)BrF₃.
C)NH₃.
D)XeF₄.

Question 66

Compound A is a solid with a melting point of 85°C,and compound B is a gas at 75°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 67

In the best Lewis structure for CN ^-,what is the formal charge on the N atom?

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

Question 68

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

A)Al₄C₃
B)CBr₄
C)CaBr₂
D)WC

Question 69

How many lone pairs are there in the Lewis structure of O₂?

A)3
B)1
C)0
D)4

Question 70

How many lone pairs are on the central Br atom in Br₃^-?

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

Question 71

Which molecule contains a triple bond?

A)O₂
B)O₃
C)HCCH
D)Br₂SO

Question 72

Classify bonds in As₄ as largely ionic,nonpolar covalent,or polar covalent.

Question 73

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

A)NaCl
B)SiO₂
C)BrF₃
D)BrF

Question 74

How many lone pairs of electrons are on the N atom in NBr₃?

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

Question 75

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

A)CH₃OH
B)Cl₂CO
C)CF₃CO₂^-
D)CO₃^2-

Question 76

How many carbon-carbon bonds are present in C₃H₈?

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

Question 77

Which one of the following is expected to exhibit resonance?

A)NH₄⁺
B)HCN
C)CS₂
D)NO₃^-

Question 78

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

A)C
B)F
C)Xe
D)He

Question 79

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

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

Question 80

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

A)N
B)O
C)Ga
D)Ne