Deck 6: Fundamentals of Chemical Bonding

Question 1

Use the concept of electronegativity to determine the polarity of a chemical bond.

Answer 1

A covalent bond arises from the mutual attraction of the bonding electrons to the two nuclei. A greater difference in electronegativity leads to a more polar bond.

Question 2

Draw optimized Lewis structures of covalent compounds, including resonance structures.

Answer 2

Only the valence electrons appear in a Lewis structure. Most atoms other than hydrogen are most stable when associated with an octet of electrons. The most likely Lewis structure has the lowest formal charges.

Question 3

Recognize the importance of the tetrahedral shape in molecules.

Answer 3

An electron group can be two electrons in a single bond, four electrons in a double bond, six electrons in a triple bond, a pair of non-bonding electrons, or a single electron. The steric number of an inner atom is the sum of the number of ligands plus the number of lone pairs. Molecular shape describes how the ligands, not the electron groups, are arranged in space. Molecular shapes can be derived from the steric number and number of ligands bonded to a central atom.

Question 4

Use the VSEPR model to predict the shapes of molecules with steric numbers 2, 3, 5, and 6.

Question 5

Understand the factors that influence bond angles, lengths, and energies.

Question 6

Which of the following is the most important component of formation of a H-Br bond?

A)
B)
C)
D)
E)

Question 7

Which of the following ranks the atoms in order of decreasing electronegativity?

A) Cl, O, Te, Mo, Rb
B) O, Cl, Mo, Rb, Te
C) Cl, O, Mo, Rb, Te
D) Rb, Mo, Te, Cl, O
E) O, Cl, Te, Mo, Rb

Question 8

Which of the following ranks the atoms in order of increasing electronegativity?

A) F, Cl, O, C, Br
B) C, Br, Cl, O, F
C) F, O, Cl, Br, C
D) C, Br, O, Cl, F
E) C, O, Br, Cl, F

Question 9

Which of the following ranks the following bonds from most polar to least polar?Cl-O, Mg-O, O-O, C-O

A) Mg-O>Cl-O>C-O>O-O
B) Cl-O>Mg-O> C-O>O-O
C) Cl-O> C-O> Mg-O> O-O
D) Mg-O> C-O> Cl-O>O-O
E) Mg-O>Cl-O>O-O> C-O

Question 10

Which of the following bonds is polar covalent?

A) LiF
B) Cl-Cl
C) Br-I
D) C-Cl
E) LiCl

Question 11

Which of the following bonds is ionic?

A) Li-F
B) Cu-Zn
C) Br-I
D) C-Cl
E) C-O

Question 12

Which of the following bonds is the least polar, but is still slightly polar?

A) Li-F
B) Fe-O
C) Br-I
D) C-C
E) C-I

Question 13

Arrange the following in order of increasing electronegativity, C, O, F, Br, Ca.

A) C < O < F < Br < Ca
B) Ca < C < O < F < Br
C) Ca < C < Br < O < F
D) Ca < C < O < Br < F
E) Ca < O < C < Br < F

Question 14

How many valence electrons are in the molecule acetic acid, CH₃CO₂H?

A) 8
B) 12
C) 16
D) 20
E) 24

Question 15

How many valence electrons are in the phosphate ion, PO₄^-3?

A) 12
B) 24
C) 28
D) 32
E) 36

Question 16

What are the formal charges on the atoms in the following Lewis structure for HNO₃?

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

Question 17

Which of the following is NOT an important resonance structure for the nitrate ion?

A)
B)
C)
D)

Question 18

What can you change when drawing resonance structures?

A) total number of bonds
B) total number atoms
C) total number of electrons
D) total number of protons
E) nature of the bonds

Question 19

How many valence electrons are there in the MnO₄^-?

A) 24
B) 32
C) 30
D) 28
E) 31

Question 20

Identify the central atom in the Lewis structure of thionyl chloride, SOCl₂ and explain basis of decision.

A) O, because it is most electronegative
B) S, because it is least electronegative
C) S, because it is largest
D) Cl, because there are two
E) O, because it is smallest

Question 21

What is the formal charge on Mn in the MnO₄^- ion?

A) 0
B) 1
C) 3
D) 5
E) 7

Question 22

Which of the following does not have a steric number of 4?

A) water
B) methane
C) ammonia
D) carbon dioxide
E) hydronium ion

Question 23

Hydridotributyltin, SnH(CH₂CH₂CH₂CH₃)₃, is used in chemical syntheses. How many atoms in this molecule have tetrahedral geometry?

A) 5
B) 7
C) 9
D) 13
E) 15

Question 24

Dimethyl hydrazine, (CH₃)₂N-NH₂, is a liquid at room temperature. How many atoms in this molecule have tetrahedral geometry?

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

Question 25

Dimethyl hydrazine, (CH₃)₂N-NH₂, is a liquid at room temperature. How many atoms in this molecule have trigonal pyramidal geometry?

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

Question 26

How many ligands are around the nitrogen atom in the molecule methylamine, CH₃NH₂?

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

Question 27

What is the steric number for the central atom in the molecule iodine triflouride, IF₃?

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

Question 28

What are the steric number and shape of thionyl chloride, SOCl₂?

A) 3, trigonal planar
B) 3, trigonal pyramidal
C) 4, trigonal pyramidal
D) 4, square pyramidal
E) 4, tetrahedral

Question 29

What is the molecular shape of the oxyanions of chlorine: ClO^-, ClO₂^-, ClO₃^- and ClO₄^-?

A) bent, bent, trigonal planar, tetrahedral
B) linear, linear, trigonal planar, tetrahedral
C) linear, bent, trigonal planar, tetrahedral
D) linear, bent, trigonal pyramidal, tetrahedral
E) linear, linear, trigonal pyramidal, tetrahedral

Question 30

What are the approximate bond angles in 1,2 dichloroethene?

A) 109.5
B) 90
C) 120
D) 115
E) 100

Question 31

Which of the following compounds (CO₂, O₃, SO₂, CS₂) are polar?

A) CO₂, SO₂, CS₂
B) CO₂, O₃, SO₂, CS₂
C) CO₂, SO₂
D) O₃, CS₂
E) O₃, SO₂

Question 32

Which of the following compounds (CH₄, CH₃Cl, CH₂Cl₂, CHCl₃ and CCl₄) are polar?

A) CCl₄, CHCl₃, CH₃Cl
B) CHCl₃, CH₃Cl
C) CHCl₃, CH₂Cl_2, CH₃Cl
D) CHCl₃, CH₂Cl_2, CH₃Cl, CCl₄
E) CHCl₃

Question 33

Which of the following molecules has a dipole moment?

A) SiCl₄
B) AlI₃
C) TeCl₄
D) PCl₅
E) CO₂

Question 34

In which of the following molecules will the bond angle be distorted from the ideal geometric values?1. SF₅⁺2. ICl₃3. BrF₅4. Si(CH₃)₄5. PF₅

A) 1, 2, and 3
B) 3 and 5
C) 2, 3, and 4
D) 4 and 5
E) 2 and 3

Question 35

Which of the following will have a dipole moment?

A) SF₆
B) CH₄
C) XeF₄
D) PH₃
E) C₂H₆

Question 36

Which is the strongest bond?

A) P - P
B) P - F
C) P - Cl
D) P - Br
E) P - I

Question 37

Which is the strongest weakest?

A) P - P
B) P - F
C) P - Cl
D) P - Br
E) P - I

Question 38

Which of the following will not have a dipole moment?

A) H₂O
B) H₂CO
C) CH₃OH
D) SF₆
E) SF₄

Question 39

Which of the following is the strongest bond?

A)
B)
C)
D)
E)

Question 40

Draw a picture showing the interaction of the valence orbitals of lithium atoms in the formation of Li₂.

Question 41

Draw a picture showing the interaction of the valence orbitals of Cl and Br in the formation of BrCl.

Question 42

Draw a diagram of energy vs. distance for the interaction of the H and Br atoms. Include sketches of the relative amounts of overlap of the orbitals. The bond energy of HBr is 363 kJ/mole and the H-Br bond length is 140.8 pm.

Question 43

Sketch the overlap of the valance orbitals in HF.

Question 44

Identify the bonding, non-bonding, and core orbitals in HBr.

Question 45

Calculate the electronegativity difference between the atoms in the bonds found below and predict which atom would be positively charged:
_O = 3.5, _N = 3.0, _Cl = 3.0, _C = 2.5,
_Al = 1.5, _Cs = 0.7
(i) N-O
(ii) Al-C
(iii) Cl-Cs

Question 46

Draw the Lewis structure of ionic compound sodium sulphite, Na₂SO₃.

Question 47

Draw the Lewis structure of dichlorodifluoromethane, CF₂Cl₂.

Question 48

Draw the Lewis structure and determine the formal charge on the central atom for BF₅.

Question 49

Draw the three most important resonance structures for the carbonate ion, CO₃^2-.

Question 50

Draw 2 important resonance structures of the thiocyanate ion, NCS^-1.

Question 51

Draw 3 resonance structures for N₂O, otherwise known as laughing gas.

Question 52

Draw Lewis structure of KF₂.

Question 53

Draw the Lewis structure for thionyl chloride, SOCl₂.

Question 54

Draw the Lewis structure of methylamine, H₃C-NH₂.

Question 55

Draw the two structural isomers of C₂H₃Cl₃.

Question 56

Draw a ball and stick model that shows the structure of methylamine, H₃CNH₂.

Question 57

Hydroxylamine has the formula NH₂(OH). Write the Lewis structure and state the molecular structure of the inner atoms.

Question 58

Hydrogen sulphide has the formula H₂S. Write the Lewis structure and state the structure of the inner atoms.

Question 59

Draw the Lewis structure and state the structure of the inner atoms for ClF₃.

Question 60

Draw the Lewis structure and state the molecular structure of the inner atoms for BrF₅.

Question 61

Write the Lewis structure and state the molecular structure of the inner atoms for SeCl₄.

Question 62

Write the Lewis structure and state the molecular structure of the inner atoms for N₂O₄.

Question 63

Write the Lewis structure and state the molecular structure of the inner atoms for AlCl₃.

Question 64

Write the Lewis structure and state the molecular structure of the inner atoms for XeO₂F₄.

Question 65

Write the Lewis structure and state the molecular structure of the inner atoms for O₃.

Question 66

Draw the two structural isomers of C₂H₃Cl₃ and determine which isomer has the greater dipole moment.

Question 67

Is the oxygen - oxygen bond longer in molecular oxygen, O₂ or ozone, O₃? Explain.

Question 68

Draw the Lewis structure and estimate the bond angles for bromine pentafluoride, BrF₅.

Question 69

Draw the Lewis structure and estimate the bond angles for phosphorous trichloride, PCl₃.

Question 70

Draw the Lewis structure and estimate the bond angles in methanol, CH₃OH.

Question 71

Which of the molecules, NH₃ or PH₃, should have the stronger bond and explain why.