Deck 8: Chemical Bonding and Climate Change

Question 1

Which of the following is the correct Lewis symbol for the oxide anion (O^2-)?

A) a
B) b
C) c
D) d

Answer 1

b

Question 2

Which of the following has the most valence electrons?

A) HF
B) NS
C) CN^-
D) ArF
E) ArF⁺

Answer 2

ArF

Question 3

Which of the following ions does not have a complete valence-shell octet?

A) B³⁺
B) I^-
C) Ca²⁺
D) Pb²⁺
E) S^2-

Answer 3

Pb²⁺

Question 4

Indicate which of the following molecules has only a single bond.

A) O₂
B) CO
C) CN^-
D) N₂
E) Cl₂

Question 5

How many valence electrons does S^2- have?

A) 8
B) 6
C) 16
D) 4
E) 14

Question 6

How many valence electrons are there in HCl?

A) 8
B) 7
C) 6
D) 2
E) 4

Question 7

Which one of the following Lewis symbols for these atoms is correct?

A) a
B) b
C) c
D) d

Question 8

A covalent bond results when __________

A) electrons are transferred from one atom to another atom.
B) atoms pool their electrons to form a "sea" of electrons.
C) atoms have outer electrons with the same principal quantum number.
D) electrons are shared between a pair of atoms.
E) an atom has 8 valence electrons.

Question 9

Indicate which of the following molecules has four shared electrons.

A) O₂
B) CO
C) HI
D) N₂
E) Cl₂

Question 10

How many valence electrons does aluminum have?

A) 1
B) 2
C) 3
D) 11
E) 13

Question 11

Indicate the ion that has 8 valence electrons.

A) H^-
B) Na⁺
C) Al³⁺
D) P^3-
E) Ar

Question 12

How many valence electrons are there in BrO^-?

A) 7
B) 6
C) 13
D) 14
E) 18

Question 13

How many valence electrons are contained in CO⁺?

A) 10
B) 11
C) 9
D) 8
E) 14

Question 14

Indicate which molecule contains the largest number of nonbonding electrons.

A) H₂
B) CO
C) N₂
D) NO
E) O₂

Question 15

Which type of bonding involves the sharing of valence electrons by two atoms?

A) covalent
B) ionic
C) polar ionic
D) intramolecular
E) metallic

Question 16

Which of the following has 13 valence electrons?

A) SH^-
B) IO
C) NO
D) ICl
E) Cl₂

Question 17

Which of the following elements has 6 valence electrons?

A) C
B) S
C) N
D) Br
E) Be

Question 18

How many shared electrons are there in the Lewis structure of CN^-?

A) 3
B) 6
C) 4
D) 2
E) 10

Question 19

Which of the following molecular ions has 3 valence electrons?

A) H₂⁺
B) He₂⁺
C) C₂⁺
D) B₂⁺
E) O₂^-

Question 20

How many shared electron pairs are there in the Lewis structure of CN^-?

A) 3
B) 6
C) 4
D) 2
E) 10

Question 21

Which of the following are listed in order of decreasing electronegativity?

A) F > S > Na > H
B) F > N > P > O
C) N > P > Si > S
D) F > Cl > Br > C
E) Te > Se > S > O

Question 22

Electronegativity increases from left to right across a period because of __________

A) increased shielding of valence electrons by the core electrons.
B) an increase in the number of protons in the nucleus.
C) a decrease in the effective nuclear charge (Z_eff).
D) an increase in the shielding of core electrons by the valence electrons.
E) a decrease in the ionization potential.

Question 23

In general, resonance __________ electrons and __________ molecules.

A) delocalizes, stabilizes
B) destabilizes, destabilizes
C) localizes, stabilizes
D) delocalizes, destabilizes
E) Localizes, stabilizes

Question 24

In which bond does the Cl atom have the highest electron density?

A) H-Cl
B) O -Cl
C) S -Cl
D) N-Cl
E) Br -Cl

Question 25

How many covalent bonds are there in SH^-?

A) 1
B) 2
C) 3
D) 0
E) 4

Question 26

Which of the following bonds is least polar?

A) H - O
B) H - N
C) H - B
D) H - C
E) H - F

Question 27

Resonance structures indicate that __________

A) there is more than one allotropic form of a compound.
B) more than one ionic form of a compound exists.
C) a molecule's electronic structure is an average or superposition of the resonance structures.
D) more than one isotopic form of an element exists in the molecule.
E) the molecule jumps back and forth between two or more different electronic structures.

Question 28

Trends in electronegativity are primarily a result of __________

A) the number of core electrons in an element.
B) an element's atomic number.
C) the effective nuclear charge (Z_eff) that an outer electron experiences.
D) the number of valence electrons of an element.
E) the atomic mass.

Question 29

Indicate which one of the following does not contain a polar covalent bond.

A) I₂
B) CO
C) HF
D) NO
E) CN^-

Question 30

In which bond does the H atom have the highest electron density?

A) H-Cl
B) H -Li
C) H -N
D) H -O
E) H -C

Question 31

How many lone-pair electrons are on each of the nitrogen atoms in the Lewis structure for dinitrogen tetroxide (N₂O₄)?

A) 0
B) 2
C) 4
D) 1
E) 3

Question 32

Which of the following bonds is most polar?

A) B - H
B) N - H
C) P - H
D) Al - H
E) C - H

Question 33

Which of the following species contains a double bond?

A) NO^-
B) F₂
C) CH
D) OH^-
E) Br₂

Question 34

Which group of elements is listed in order of increasing electronegativity?

A) F < Cl < Ge < Sn
B) Rb < Ca < Sc < Cs
C) Zr < V < Nb < Ta
D) In < Ga < Al < C
E) Cl < Br < I < F

Question 35

Indicate the element with the largest electronegativity.

A) K
B) Cs
C) Mg
D) B
E) Li

Question 36

Which of the following properties is typically used to predict the type of bond that forms between two elements?

A) electronegativity
B) ionization energy
C) atomic radius
D) electron affinity
E) atomic mass

Question 37

Which of the following is most likely a polar covalent bond?

A) Na -Cl
B) H -H
C) C -N
D) K -F
E) Ca -O

Question 38

Indicate the element with the smallest electronegativity.

A) Cl
B) F
C) Be
D) K
E) C

Question 39

Identify the molecule or ion that contains a polar covalent bond.

A) O₂
B) N₂
C) CN^-
D) H₂
E) I₂

Question 40

How many covalent bonds are there in CN^-?

A) 1
B) 2
C) 3
D) 0
E) 4

Question 41

What is the formal charge of the nitrogen atom in hydrogen cyanide (HCN)?

A) -1
B) 0
C) 1
D) 5
E) 2

Question 42

The formal charge on the oxygen atoms in the Lewis structure for sulfur dioxide (SO₂) that minimizes the formal charges is __________

A) 0 for both oxygen atoms.
B) +1 for both oxygen atoms.
C) -1 for both oxygen atoms.
D) 0 for one oxygen atom, -1 for the other.
E) +1 for one oxygen atom, -1 for the other.

Question 43

Ammonium nitrate (NH₄NO₃) is often used as a fertilizer. How many reasonable Lewis structures can be drawn for the ammonium ion ?

A) 0
B) 1
C) 2
D) 3
E) 4

Question 44

What is the formal charge on the central nitrogen atom in dinitrogen sulfide (N₂S)?

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

Question 45

Which of the following molecules contains an exception to the octet rule?

A) NO
B) CO
C) HBr
D) I₂
E) N₂O

Question 46

Which of the following atoms can have an expanded octet?

A) S
B) C
C) N
D) B
E) Be

Question 47

When sulfur-containing fuels are burned, sulfur trioxide (SO₃) is formed in the atmosphere and contributes to acid rain (sulfur trioxide plus water produces sulfuric acid). How many resonance structures are there for SO₃ when each atom satisfies the octet rule?

A) 0
B) 1
C) 2
D) 3
E) 4

Question 48

How many lone-pair electrons are on the central oxygen atom in the Lewis structure for dinitrogen pentoxide (N₂O₅)?

A) 0
B) 2
C) 4
D) 1
E) 3

Question 49

What is the total number of electrons assigned to the oxygen atom in the Lewis structure of formaldehyde (H₂CO)?

A) 8
B) 6
C) 4
D) 2
E) 10

Question 50

Vinegar is a solution of acetic acid (C₂H₄O₂) and water. Which of the following is the Lewis structure for acetic acid?

A) a
B) b
C) c
D) d

Question 51

The formal charge of an atom in a Lewis structure is defined as __________

A) the difference between the number of bonding electrons and nonbonding electrons assigned to an atom.
B) the difference between the number of valence electrons in a free atom and the total number of valence electrons in the molecule.
C) the difference between the number of valence electrons in a free atom and the number of electrons assigned to it in a Lewis structure.
D) the difference between the number of valence electrons in a free atom and the number of bonding electrons assigned to it.
E) the difference between the number of valence electrons in a free atom and the number of nonbonding electrons assigned to it.

Question 52

How many bonding electrons are assigned to the nitrogen in the Lewis structure of ammonia (NH₃)?

A) 3
B) 6
C) 5
D) 8
E) 4

Question 53

Which one of the following molecules or ions contains an exception to the octet rule?

A) O₂
B) CN^-
C) XeCl
D) ClO^-
E) SiH₄

Question 54

What is the formal charge of the carbon atom in the Lewis structure for carbonyl sulfide (OCS)?

A) 0
B) -2
C) 1
D) 4
E) 2

Question 55

Which of the following compounds would be the least stable?

A) SF₆
B) SeI₅
C) CF₄Cl
D) PCl₂F₃
E) CF₂Cl₂

Question 56

What types of bonds form between the chlorine and oxygen atoms of the chlorite ion (ClO₂^-)?

A) single
B) between single and double
C) double
D) triple
E) ionic

Question 57

Nitrite (NO₂^-) is an important nutrient in the eutrophic zone of the ocean. Which of the following is the correct set of resonance structures for this ion?

A) a
B) b
C) c
D) d

Question 58

How many total electrons are assigned to the nitrogen atom in the Lewis structure of ammonia (NH₃)?

A) 3
B) 6
C) 5
D) 8
E) 4

Question 59

Which structure for dinitrogen sulfide (N -N -S or N -S -N) is the more stable?

A) N -N -S, because the formal charges are all 0
B) N -N -S, because the formal charges are smaller
C) N -S -N, because the formal charges are smaller
D) N -S -N, because the formal charges are all 0
E) N -S -N, because it is symmetrical and the formal charges are the same for both N atoms

Question 60

Carbon dioxide is a greenhouse gas. Which of the following is the correct Lewis structure for carbon dioxide?

A)
B)
C)
D)

Question 61

Which of the following is the shortest bond? The number in parentheses is the bond energy.

A) C - C (348 kJ/mol)
B) C - F (453 kJ/mol)
C) C - H (411 kJ/mol)
D) C - Cl (339 kJ/mol)
E) C - O (358 kJ/mol)

Question 62

Which of the following bonds will be the shortest?

A) C O
B) N O
C) S O
D) N N

Question 63

Based on electronegativities, which one of the following would have ionic bonds?

A) O₂
B) MgCl₂
C) H₂O
D) CF₄
E) SiO₂

Question 64

How many valence electrons surround the xenon atom in xenon tetrafluoride (XeF₄)?

A) 8
B) 4
C) 10
D) 12
E) 6

Question 65

How many lone-pair electrons are on the central atom of xenon tetrachloride? (XeCl₄)?

A) 2
B) 4
C) 8
D) 10
E) 6

Question 66

Which of the following is the longest bond? The number in parentheses is the bond energy.

A) C - C (348 kJ/mol)
B) C - F (453 kJ/mol)
C) C - H (411 kJ/mol)
D) C - Cl (339 kJ/mol)
E) C - O (358 kJ/mol)

Question 67

Which of the following compounds is likely to have the least reactive hydrogen?

A) H -Br (141 pm)
B) H -I (161 pm)
C) H -Cl (127 pm)
D) H-F (92 pm)
E) H₂S (134m)

Question 68

In a chemical reaction, bonds are broken and new bonds are formed. Which one of the following statements regarding bond energies is correct?

A) Energy is released when bonds are broken.
B) Energy is released when bonds are broken and more stable bonds are formed.
C) Energy is released when bonds are broken and less stable bonds are formed.
D) Bond energies and bond lengths generally are not correlated, i.e., they vary independently.
E) Bond energies and bond order are unrelated to each other.

Question 69

Which of the following compounds would have the largest enthalpy of formation? The bond energies are given in parentheses.

A) H-Br (366 kJ/mol)
B) H -I (299 kJ/mol)
C) H -Cl (431 kJ/mol)
D) H -F (567 kJ/mol)
E) H -H (436 kJ/mol)

Question 70

Odd electron molecules are called __________

A) anions.
B) cations.
C) radicals.
D) isomers.
E) weird.

Question 71

In which of the following molecules does the central atom have an expanded octet?

A) N₂O
B) PCl₅
C) BeF₂
D) AsF₃
E) NO₂

Question 72

Identify the molecule below that contains a double bond.

A) HCN
B) O₃
C) C₂H₂
D) S₂
E) N₂

Question 73

Use the formal charge as a criterion to identify the Lewis structure below that is most stable.

A)
B)
C)
D)
E)

Question 74

Bond length and bond strength are __________

A) inversely proportional.
B) directly proportional.
C) identical.
D) unrelated.
E) arbitrary.

Question 75

How many valence electrons are there in a correctly drawn Lewis structure for formamide, HCONH₂?

A) 12
B) 14
C) 16
D) 18
E) 20

Question 76

Which of the following oxoacids would you predict not to exist?

A) HFO₄
B) HClO₄
C) HBrO₄
D) HIO₄
E) HClO

Question 77

Acetonitrile (CH₃CN) is an important industrial chemical. Among other things, it is used to make plastic moldings, which have multiple uses, from car parts to Lego bricks. Which one of the following statements about acetonitrile is not correct?

A) Acetonitrile has 16 valence electrons.
B) Acetonitrile has one triple bond.
C) Acetonitrile has one pair of nonbonding electrons.
D) All atoms satisfy the octet rule in acetonitrile.
E) One carbon atom and the nitrogen atom have nonzero formal charges.

Question 78

Which of the following has the strongest bond? The number in parentheses is the bond length.

A) H - Br (141 pm)
B) H - I (161 pm)
C) H - Cl (127 pm)
D) H - F (92 pm)
E) H - S (134 pm)

Question 79

Which of the following bonds is the weakest?

A) C -O
B) C O
C) O O
D) O O

Question 80

An element can form single, double, triple, and quadruple bonds between its atoms. Which will be the shortest?

A) single
B) double
C) triple
D) quadruple