Deck 4: The Covalent Bond

Question 1

Which of the following elements has five valence electrons?

A) Sr
B) K
C) Si
D) Se
E) As

Answer 1

As

Question 2

Which of the following elements has 2 valence electrons?

A) Ca
B) Ga
C) Ge
D) As
E) Se

Answer 2

Ca

Question 3

How many valence electrons are in the IF₂^- ion?

A) 7
B) 14
C) 20
D) 21
E) 22

Answer 3

22

Question 4

Which of the following species has all its electrons paired?

A) Fe³⁺
B) Zn²⁺
C) ClO₂
D) NO
E) NO₂

Question 5

How many $\textbf{ pairs }$ of nonbonding electrons are in the valence shell of the iodine atom in the IF₂^- ion?

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

Question 6

How many $\textbf{ pairs }$ of nonbonding electrons are in the valence shell of the iodine atom in the ICl₄^- ion?

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

Question 7

How many nonbonding $\textbf{ electrons }$ are on the central atom in the Lewis structure of xenon tetrafluoride?

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

Question 8

How many $\textbf{ pairs }$ of bonding electrons can be found in the valence shell of
The nitrogen atom in HNO₂? (Hint: the skeleton structure is HONO)

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

Question 9

How many $\textbf{ pairs }$ of nonbonding electrons can be found on the chlorine atom in chlorous acid, HOClO?

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

Question 10

Which of the following elements would form an XF₆^2- ion that has no nonbonding electrons in the valence shell of the central atom?

A) Ca
B) C
C) Si
D) S
E) P

Question 11

Nitrous oxide (N₂O) is an anesthetic commonly known as "laughing gas." Which of the following is a correct Lewis structure for this compound?

A)
B)
C)
D)
E)

Question 12

Which element would form XF₅ for which there are no nonbonding electrons in the Lewis structure?

A) N
B) Al
C) Si
D) P
E) Br

Question 13

If X is a 3rd row element and XCl₃ has the Lewis structure
X must be:

A) Al
B) Si
C) P
D) S
E) Cl

Question 14

If the XF₆^- ion has the Lewis structure

X could be which of the following elements?

A) N
B) Al
C) Si
D) P
E) Br

Question 15

Assume that the XF₃ molecule has the following Lewis structure.

The molecule could be:

A) boron trifluoride, i.e., X = B
B) nitrogen trifluoride, i.e., X = N
C) chlorine trifluoride, i.e., X = Cl
D) phosphorus trifluoride, i.e., X = P
E) more than one of the above

Question 16

Which of the following elements would form a compound with the following Lewis structure?

A) Al
B) Si
C) P
D) S
E) Cl

Question 17

If there are two pairs of nonbonding electrons in the valence shell of the central atom in the XF₄^- ion, in which Group of the periodic table does the element X belong?

A) Group IVA
B) Group VA
C) Group VIA
D) Group VIIA
E) Group VIIIA

Question 18

What is element X in the following Lewis structure?

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

Question 19

Which of the following species contains only single bonds?

A) CN^-
B) NO⁺
C) CO
D) O₂^2-
E) Cl₂CO

Question 20

Which of the following would be the best Lewis structure for NOCl?

A)
B)
C)
D)
E)

Question 21

Which of the following compounds would have the same Lewis structure as the N₂ molecule?

(I) F₂ (II) CO (III) NO (IV) CN^- (V) NO⁺

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

Question 22

The correct Lewis structure for CH₂Cl₂ contains:

A) 2 single bonds, 2 double bonds and no nonbonding electrons
B) 4 single bonds and no nonbonding electrons
C) 4 single bonds and four nonbonding electrons
D) 2 single bonds, 2 double bonds, and eight nonbonding electrons
E) 4 single bonds and 12 nonbonding electrons

Question 23

The correct Lewis structure for the NO₂⁺ ion has:

A) 2 double bonds and eight nonbonding electrons
B) 1 double bond, 1 single bond, and 12 nonbonding electrons
C) 2 single bonds and 12 nonbonding electrons
D) 2 triple bonds and 4 nonbonding electrons
E) 1 single bond, 1 double bond, and 8 nonbonding electrons

Question 24

In which Group of the periodic table does element X belong if there are one pair of nonbonding electrons in the valence shell of the central atom in the XF₄^- ion?

A) Group IIIA
B) Group IVA
C) Group VA
D) Group VIA
E) none of these

Question 25

Which element forms a compound with the following Lewis structure?

A) Al
B) Si
C) P
S) S
E) I

Question 26

Which of the following are exceptions to the Lewis octet rule?

(I) CO₂ (II) BeF₂ (III) SF₄ (IV) SO₃ (V) PCl₃

A) I and II
B) II and III
C) III and IV
D) I, II and III
E) none of these are exceptions to the Lewis octet rule

Question 27

Which of the following are exceptions to the Lewis octet rule?

(I) BF₃ (II) H₂CO (III) XeF₄ (IV) H₃O⁺ (V) ClF₃

A) I and II
B) I and III
C) I, III and V
D) II and III
E) III and V

Question 28

Which of the following elements is the most likely to follow the octet rule?

A) H
B) C
C) Si
D) As
E) All of these elements must follow the octet rule.

Question 29

Which of the bonds in ethanol, CH₃CH₂OH, would have a bond length of approximately 0.103 nm?

Covalent Radii: H = 0.037 nm, C = 0.077 nm, O = 0.066 nm

A) C-C
B) C-O
C) C-H
D) O-H
E) not enough information is given

Question 30

Which of the following compounds/ions has the shortest C-O bond length?

A) CH₃OH
B) H₂CO
C) CO₃^2-
D) CH₃CH₂OH
E) all C-O bonds are the same length

Question 31

Which of the following bond lengths is the largest?

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

Question 32

Which bond length is the shortest in the following compound?

A) HF-C
B) Cl-C
C) F-C
D) C-O
E) O-H

Question 33

In which of the following is the carbon to oxygen bond the shortest?

A)
B)
C)
D)
E) all C-O bonds are the same length

Question 34

Which of the following compounds contains the strongest carbon-nitrogen bond? (Hint: Look at their Lewis structures)

A) H₂CNH
B) HCN
C) H₃CNH₂
D) H₃CNO
E) all of these molecules contain C-N single bonds

Question 35

Which of the following molecules or ions is not a resonance hybrid?

A) SCN^-
B) CO₃^2-
C) C₂H₄
D) N₂O
E) all are resonance hybrids

Question 36

What is the difference between an isomer and a resonance structure?

Question 37

Which of the following would be a resonance structure for the compound shown below.

A)
B)
C)
D)
E) none of these

Question 38

Which of the following molecules is best described with two resonance structures?

A) NO₂^-
B) H₂O
C) OF₂
D) ClNO
E) BeF₂

Question 39

Which of the following isn't a resonance hybrid?

A) CO₂
B) NO₂^-
C) N₂O
D) SO₃
E) SCN^-

Question 40

Which of the following are resonance hybrids?

(I) HCO₂^- (II) PH₃ (III) HCN (IV) SO₄^2- (V) NO₂

A) I
B) II and IV
C) IV and V
D) I and IV
E) I and V

Question 41

Which of the following can be used to predict an element's electronegativity?

A) average valence electron energy
B) Lewis Structures
C) bond angles
D) bond length
E) resonance

Question 42

Which of the following elements has the greatest electronegativity?

A) Mg
B) Cu
C) S
D) As
E) Sr

Question 43

Which of the following lists the elements in the correct order of increasing electronegativity?

A) Si < S < O
B) S < Si < O
C) S < O < Si
D) Si < O < S
E) O < Si < S

Question 44

Which of the following is the best true description of the charge on an atom within a molecule?

A) oxidation number
B) partial charge
C) formal charge
D) all of these are equally good
E) none of these

Question 45

In which of the following compounds is the bond the least polar?

A) NaCl
B) CH₄
C) CO
D) Cl₂
E) HCl

Question 46

Use formal charge to decide which of the following skeleton structures will give the best Lewis structure of the molecule. Show the values of formal charge and explain your choice of the best structure.

Question 47

The "zwitterion" form of the amino acid glycine is:
H₃N⁺CH₂CO₂^-. The properties of the various amino acids depend heavily on the presence (or absence) of charge on the side chain. Consider the amino acid arginine, for example, which has the following Lewis structure:

Determine the Formal Charge on the nitrogens labeled 1, 2 and 3.

A) N(1) = 0, N(2) = +1, and N(3) = 0
B) N(1) = 0, N(2) = -1, and N(3) = 0
C) N(1) = +1, N(2) = 0, and N(3) = +1
D) N(1) = -1, N(2) = 0, and N(3) = -1
E) N(1) = +1, N(2) = 0, and N(3) = -1

Question 48

Our response to the anthrax scare was a 20-year-old antibacterial known as ciprofloxacin or "Cipro."


Apply the concept of formal charge to the three nitrogen atoms labeled 1, 2 and 3. Are they neutral, negatively charged, or positively charged?

A) N(1) = -1, N(2) = -1, and N(3) = -1
B) N(1) = -1, N(2) = 0, and N(3) = 0
C) N(1) = 0, N(2) = 0, and N(3) = 0
D) N(1) = 0, N(2) = +1, and N(3) = +1
E) N(1) = +1, N(2) = +1, and N(3) = +1

Question 49

Which element will combine with sulfur to form a linear molecule with the formula XS₂?

A) Li
B) B
C) C
D) O
E) F

Question 50

In which compound are the valence electrons on the sulfur arranged towards the corners of a tetrahedron?

A) SF₃⁺
B) SF₄
C) SF₅
D) SF₆
E) both SF₄ and SF₆

Question 51

What is the distribution of electrons around the S atom in H₂SO₄?
[Hint: The skeleton structure of this oxyacid is O₂S(OH)₂.

A) linear
B) trigonal planar
C) tetrahedral
D) trigonal bipyramidal
E) octahedral

Question 52

What is the distribution of the oxygen atoms around the N atom in HNO₃?
[Hint: The skeleton structure of this oxyacid is HONO₂]

A) linear
B) trigonal planar
C) tetrahedral
D) trigonal bipyramidal
E) octahedral

Question 53

The bond angles in most symmetric, AB_x, molecules are the same. Which of the following is an exception to this rule?

A) NH₃
B) SF₆
C) PCl₅
D) SO₃
E) CO₂

Question 54

Which term best describes the shape of the I₃^- ion?

A) linear
B) bent
C) trigonal planar
D) trigonal pyramidal
E) trigonal bipyramidal

Question 55

What is the molecular geometry of the compound formed by the reaction of nitrogen with fluorine?

A) bent
B) trigonal planar
C) trigonal pyramidal
D) trigonal bipyramidal
E) none of the above

Question 56

What is the molecular geometry of the SF₅⁺ ion?

A) see-saw
B) square planar
C) square pyramidal
D) trigonal bipyramidal
E) octahedral

Question 57

What is the best description of the structure of the SF₃⁺ ion?

A) bent or angular
B) trigonal planar
C) trigonal pyramidal
D) tetrahedral
E) trigonal bipyramidal

Question 58

The molecular structure of the IO₃^- ion is best described as:

A) bent or angular
B) trigonal planar
C) trigonal pyramidal
D) trigonal bipyramidal
E) T-shaped

Question 59

Which of the following molecules has a trigonal planar shape?

A) BeCl₂
B) PCl₃
C) ICl₂⁺
D) BF₃
E) H₃O⁺

Question 60

Which of the following molecules are tetrahedral?

(I) SiF₄ (II) CH₄ (III) NF₄⁺ (IV) BF₄^- (V) TeF₄

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

Question 61

Which of the following molecules or ions doesn't have a tetrahedral shape?

A) SiF₄
B) NF₄⁺
C) BF₄^-
D) SeF₄
E) CF₄

Question 62

Which of the following molecules or ions isn't planar?

A) NH₃
B) BF₃
C) CO₃^2-
D) NO₃^-
E) none of these molecules or ions are planar

Question 63

What is the best description of the shape of the TeH₂ molecules?

A) linear
B) bent
C) trigonal planar
D) tetrahedral
E) seesaw

Question 64

Metformin is the chemical name for a prescription drug sold as "glucophage," which is an oral hypoglycemic. In other words, a pill that lowers blood sugar levels so that adult on-set diabetics don't have to inject themselves with insulin. The Lewis structure of metformin is shown below.


Use the electron domain model to predict the geometry around the nitrogen atom in the center of the molecule, e.g., N(3).

A) bent or angular
B) trigonal planar
C) trigonal pyramidal
D) trigonal bipyramidal
E) tetrahedral

Question 65

Terpin hydrate is an expectorant that was used for many years by people with serious coughs, such as those suffering from pneumonia.


Use the electron domain model to predict the distribution of electron domains in the valence shell of the oxygen atoms in this compound.

A) linear
B) bent or angular
C) trigonal planar
D) tetrahedral
E) trigonal bipyramidal

Question 66

When the rare gas elements (He, Ne, Ar, Kr, Xe and Rn) were first
Discovered, a sample of Ar was sent to Moissan, who had discovered the most active of the known elements: F₂. The failure of Moissan's attempts to react argon with fluorine, coupled with repeated failures by other chemists to get the more abundant of these gases to undergo chemical reaction, eventually led to their being labeled inert gases. We now know this isn't so. Xe reacts with F₂ to form a variety of compounds, including XeF₄. Which of the following best describes the XeF₄ molecule?

A) Trigonal bipyramidal distribution of valence electrons on the Xe with a T-shaped molecular geometry.
B) Trigonal bipyramidal distribution of valence electrons on the Xe with a trigonal planar molecular geometry.
C) Trigonal bipyramidal distribution of valence electrons on the Xe with a pyramidal molecular geometry.
D) Octahedral distribution of valence electrons on the Xe with a square planar molecular geometry.
E) Octahedral distribution of valence electrons on the Xe with a seesaw molecular geometry.

Question 67

An element Z forms a molecular compound ZBr₃ that is found to have trigonal pyramidal molecular geometry. The element Z must be in which group in the periodic table?

A) IIIA
B) IVA
C) VA
D) VIA
E) VIIA

Question 68

Tellurium hydride is one of the foulest smelling compounds known. How many pairs of nonbonding electrons are in the valence shell of the tellurium atom in TeH₂?

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

Question 69

There is a single pair of nonbonding electrons on the central atom in the Lewis structure of ICl₅. This molecule has:

A) a trigonal pyramidal distribution of electrons and an octahedral molecular geometry.
B) an octahedral distribution of electrons and a square pyramidal geometry.
C) a trigonal bipyramidal distribution of electrons and a seesaw molecular geometry.
D) an octahedral distribution of electrons and a trigonal bipyramidal geometry.
E) a trigonal bipyramidal distribution of electrons and trigonal bipyramidal geometry.

Question 70

Which of the following molecules are linear?

(I) C₂H₂ (II) CO₂ (III) NO₂^- (IV) NO₂⁺ (V) H₂O

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

Question 71

Which of the following has a square-planar geometry?

A) SF₄
B) ClO₄^-
C) CCl₄
D) ICl₄^-
E) PO₄^3-

Question 72

Which of the following species isn't planar?

A) SO₃
B) SO₃^2-
C) SO₂
D) BF₃
E) NO₃^-

Question 73

What is the molecular geometry of xenon tetrafluoride?

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

Question 74

The shape of the NO₂^- ion is best described as:

A) linear
B) T-shaped
C) bent
D) square planar
E) pyramidal

Question 75

How many pairs of nonbonding electrons are in the valence shell of the central iodine atom in the I₃^- ion?

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

Question 76

The Raschig process involves the reaction between ammonia and the hypochlorite ion to form hydrazine, which has been used as a rocket fuel.

2 NH₃(aq) + OCl^-(aq) $\rightarrow$ H₂NNH₂(g) + Cl^-(aq) +H₂O(l)
There are isolated cases of individuals making hydrazine unexpectedly in their homes when cleaning a commode. They start with a cleaner that contains ammonia, and then, when this doesn't work, they mix it with a cleaner (such as Chlorox) that contains the hypochlorite ion. How many pairs of nonbonding electrons can be found on each nitrogen atom in the hydrazine molecule? (Note: Assume that there is a bond between the two nitrogen atoms in hydrazine.)

A) 0
B) 1
C) 2
D) 3
E) The two N atoms contain a different number of nonbonding electrons.

Question 77

Which of the following compounds/ions contains a bond angle of 120 11 ?

A) CH₃OH
B) CO₃^2-
C) CO₂
D) CH₃Cl
E) CH₂Cl₂

Question 78

Estimate the hydrogen-phosphorus-hydrogen bond angle in PH₃.

A) approximately 90
B) approximately 109
C) approximately 120 11ee9eaa_79d4_764b_9fac_596588eaddbc_TB9692_11
D) approximately 180 11ee9eaa_79d4_764b_9fac_596588eaddbc_TB9692_11
E) approximately 150 11ee9eaa_79d4_764b_9fac_596588eaddbc_TB9692_11

Question 79

Which one of the following molecular geometries has bond angles which are $\underline{\text{ not }}$ all equal?

A) tetrahedral
B) trigonal planar
C) trigonal bipyramidal
D) octahedral
E) none of these

Question 80

For the molecule below, which of the bond angles is (are) about 120 ?

A) C-C=O
B) H-C-C
C) C-O-H
D) O-C=O
E) both a & d