Deck 10: The Shapes of Molecules

Question 1

Which one of the following Lewis structures is definitely incorrect?

A)A
B)B
C)C
D)D
E)E

Answer 1

E

Question 2

In a Lewis structure for a molecule or ion, the sum of the formal charges on the atoms is equal to the charge on the molecule or ion.

Answer 2

True

Question 3

The Lewis structure of NO₂ violates the octet rule.

Answer 3

True

Question 4

Select the correct Lewis structure for NOCl, a reactive material used as an ionizing solvent.

A)
B)
C)
D)
E)None of these choices are correct.

Question 5

Bond angles of 180° only occur around atoms which display linear molecular geometry.

Question 6

A molecule that contains polar bonds will always have a dipole moment.

Question 7

Select the best Lewis structure for ClCN.

A)
B)
C)
D)
E)

Question 8

All possible resonance structures contribute equally to the resonance hybrid.

Question 9

Which one of the following Lewis structures is definitely incorrect?

A)
B)
C)
D)
E)

Question 10

In formaldehyde, CH₂O, both the formal charge and the oxidation number of carbon are zero.

Question 11

Oxygen difluoride is a powerful oxidizing and fluorinating agent. Select its Lewis structure.

A)
B)
C)
D)
E)None of these choices are correct.

Question 12

Select the correct Lewis structure for nitrogen trifluoride, NF₃.

A)
B)
C)
D)
E)

Question 13

The molecule AX₂, where A and X are different elements, will have a dipole moment if the molecule is bent.

Question 14

In order for a noncyclic triatomic molecule to be bent, VSEPR theory requires that there must be two lone pairs on the central atom.

Question 15

In neutral molecules, how many bonds are commonly formed by nitrogen? And how many by oxygen?

A)5 and 6
B)4 and 2
C)3 and 6
D)4 and 6
E)3 and 2

Question 16

Boron never achieves an octet in any of its compounds.

Question 17

When resonance occurs, the bond lengths in a molecule fluctuate rapidly.

Question 18

Hydrazine, N₂H₄, is a good reducing agent that has been used as a component in rocket fuels. Select its Lewis structure.

A)
B)
C)
D)
E)None of these choices are correct.

Question 19

According to VSEPR theory, a molecule with the general formula AX₃E₂ (where E represents a lone pair on A) will be trigonal planar.

Question 20

Which one of the following Lewis structures is definitely incorrect?

A)A
B)B
C)C
D)D
E)E

Question 21

In the nitrate ion (NO₃⁻), nitrogen and oxygen are held together by

A)ionic interactions.
B)covalent bonds.
C)dative bonds.
D)electronegativity.
E)network bonds.

Question 22

Select the best Lewis structure for P₂I₄.

A)
B)
C)
D)
E)None of these choices are correct.

Question 23

Select the Lewis structure for XeO₂F₂ that correctly minimizes formal charges.

A)
B)
C)
D)
E)

Question 24

In which of the following does the nitrogen atom have a formal charge of −1?

A)
B)
C)
D)
E)

Question 25

Select the Lewis structure in which formal charges are minimized for the periodate anion, IO₄⁻.

A)
B)
C)
D)
E)

Question 26

In which one of the following is the best Lewis structure a resonance structure? (central atoms are bold)

A)CO ₂
B)ClO ₃ ⁻
C)COCl ₂
D)NO ₂ ⁺
E)HCN

Question 27

In which one of the following species is the best Lewis structure a resonance structure?

A)NH ₃
B)CO ₂
C)SF ₆
D)O ₂
E)CO ₃ ²⁻

Question 28

How many resonance structures are possible for NO₃⁻?

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

Question 29

In carbon disulfide, how many lone pairs of electrons are on each sulfur atom?

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

Question 30

Thionyl chloride is used as an oxidizing and chlorinating agent in organic chemistry. Select the best Lewis structure for SOCl₂.

A)
B)
C)
D)
E)None of these choices are correct.

Question 31

Phosphoryl iodide is used in the preparation of organophosphorus derivatives and phosphate esters. Select the Lewis structure for POI₃ that minimizes formal charges.

A)
B)
C)
D)
E)

Question 32

The best Lewis structure for sulfuric acid has zero formal charges, sulfur as the central atom, and no bonds between S and H. How many single and double bonds, respectively, are there in this Lewis structure?

A)2 single, 4 double
B)4 single, 2 double
C)4 single, no double
D)6 single, no double
E)5 single, 1 double

Question 33

Select the correct Lewis structure for TeBr₂.

A)
B)
C)
D)
E)

Question 34

Which one of the following molecules contains a double bond?

A)N ₂
B)PCl ₅
C)CH ₂O
D)C ₂H ₂
E)I ₂

Question 35

In which one of the following is the best Lewis structure a resonance structure?

A)SO ₃
B)BF ₃
C)I ₃ ⁻
D)SCO (C = central atom)
E)SO ₃ ²⁻

Question 36

In the following Lewis structure for ClO₃F, chlorine has a formal charge of __________ and an oxidation number of __________.

A)7; 7
B)7; −1
C)1; 1
D)1; −1
E)1; 7

Question 37

The formal charges on Cl and O in the structure shown for the ClO⁻ ion are, respectively

A)0 and −1
B)−1 and 0
C)1 and −2
D)−2 and 1
E)None of these choices are correct.

Question 38

In which one of the following molecules are all the bonds single?

A)O ₃
B)POCl ₃
C)CO
D)COCl ₂
E)N ₂H ₄

Question 39

In the following Lewis structure for phosphate, phosphorus has a formal charge of __________ and an oxidation number of __________.

A)0; −3
B)0; 5
C)5; −3
D)5; 5
E)3; 5

Question 40

How many electron pairs are shared between the carbon atoms in C₂H₄?

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

Question 41

In which one of the following structures does the central atom have a formal charge of +2?

A)
B)
C)
D)
E)

Question 42

According to VSEPR theory, a molecule with the general formula AX₄E will have a __________ molecular shape.

A)bent
B)see-saw
C)trigonal planar
D)T-shaped
E)square planar

Question 43

According to VSEPR theory, a molecule with the general formula AX₄ will have a __________ molecular shape.

A)bent
B)trigonal planar
C)trigonal pyramidal
D)square planar
E)tetrahedral

Question 44

According to VSEPR theory, a molecule with the general formula AX₆ will have a __________ molecular shape.

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

Question 45

The formal charge on Cl in the structure shown for the perchlorate ion is

A)−2
B)−1
C)0
D)+1
E)+2

Question 46

According to VSEPR theory, a molecule with the general formula AX₃E will have a __________ molecular shape.

A)bent
B)trigonal planar
C)trigonal pyramidal
D)tetrahedral
E)triangular

Question 47

In which one of the following species is the central atom (the first atom in the formula) an exception to the octet rule?

A)NH ₃
B)NH ₄ ⁺
C)I ₂
D)BH ₄ ⁻
E)SF ₆

Question 48

According to VSEPR theory, a molecule with the general formula AX₂ will have a __________ molecular shape.

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

Question 49

According to VSEPR theory, a molecule with the general formula AX₃E₂ will have a __________ molecular shape.

A)trigonal pyramidal
B)trigonal bipyramidal
C)trigonal planar
D)T-shaped
E)see-saw

Question 50

According to VSEPR theory, a molecule with the general formula AX₃ will have a __________ molecular shape.

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

Question 51

How many faces and how many vertexes (corners), respectively, are there in a trigonal bipyramid?

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

Question 52

Which of the following atoms can expand its valence shell when bonding?

A)N
B)C
C)O
D)P
E)Al

Question 53

In which one of the following species is the central atom (the first atom in the formula) likely to violate the octet rule?

A)BF ₄ ⁻
B)XeO ₃
C)SiCl ₄
D)NH ₃
E)CH ₂Cl ₂

Question 54

According to VSEPR theory, a molecule with the general formula AX₂E₂ will have a __________ molecular shape.

A)linear
B)bent
C)trigonal planar
D)tetrahedral
E)see-saw

Question 55

According to VSEPR theory, a molecule with the general formula AX₅ will have a __________ molecular shape.

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

Question 56

According to VSEPR theory, a molecule with the general formula AX₂E will have a __________ molecular shape.

A)bent
B)see-saw
C)trigonal planar
D)T-shaped
E)trigonal pyramidal

Question 57

According to VSEPR theory, a molecule with the general formula AX₂E₃ will have a __________ molecular shape.

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

Question 58

In the COCl₂ molecule, carbon is the central atom. Based on the best Lewis structure for COCl₂, what is the formal charge on carbon?

A)0
B)+1
C)−1
D)+2
E)−2

Question 59

Considering all the bonds in a molecule with trigonal bipyramidal geometry, what are the bond angles present?

A)120° only
B)90° only
C)180° only
D)60° and 90° only
E)90°, 120°, and 180°

Question 60

According to VSEPR theory, a molecule with the general formula AX₄E₂ will have a __________ molecular shape.

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

Question 61

Use VSEPR theory to decide which one of the following ions and molecules is likely to be planar. (The central atom is always first in the formula.)

A)BrF ₃
B)H ₃O ⁺
C)PCl ₃
D)SO ₄ ²⁻
E)SF ₄

Question 62

According to VSEPR theory, a molecule with the general formula AX₅E will have a __________ molecular shape.

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

Question 63

What is the molecular shape of XeO₂F₂ as predicted by the VSEPR theory?

A)Square planar
B)Tetrahedral
C)Square pyramidal
D)See-saw
E)Octahedral

Question 64

What is the molecular shape of NOCl as predicted by the VSEPR theory?

A)Linear
B)Trigonal planar
C)Bent
D)Tetrahedral
E)Trigonal pyramidal

Question 65

What is the molecular shape of N₂O as predicted by the VSEPR theory?

A)Trigonal pyramidal
B)Trigonal planar
C)Angular
D)Bent
E)Linear

Question 66

What is the molecular symmetry around the carbons in CCl₂CH₂ as predicted by the VSEPR theory?

A)linear
B)Trigonal planar
C)V-shaped
D)Tetrahedral
E)Trigonal pyramidal

Question 67

What is the molecular shape of NO₂⁻ as predicted by the VSEPR theory?

A)Linear
B)Trigonal planar
C)Bent
D)Tetrahedral
E)Resonant

Question 68

What is the molecular shape of the thiocyanate anion, SCN⁻, as predicted by the VSEPR theory? (Carbon is the central atom.)

A)Linear
B)Bent
C)Angular
D)Trigonal
E)None of these choices are correct.

Question 69

What is the molecular shape of BeH₂ as predicted by the VSEPR theory?

A)Linear
B)Bent
C)Angular
D)Trigonal
E)None of these choices are correct.

Question 70

Which one of the following molecules and ions will have a planar geometry?

A)PCl ₃
B)BF ₄ ⁻
C)XeF ₄
D)BrF ₅
E)H ₃O ⁺

Question 71

What is the molecular shape of ClF₄⁻ as predicted by the VSEPR theory?

A)Square pyramidal
B)Square planar
C)See-saw
D)Octahedral
E)Tetrahedral

Question 72

What is the molecular shape of ClO₃F as predicted by the VSEPR theory?

A)Trigonal pyramidal
B)Square planar
C)Square pyramidal
D)Tetrahedral
E)Octahedral

Question 73

What is the molecular shape of SCl₃F as predicted by the VSEPR theory?

A)Linear
B)Bent
C)See-saw
D)T-shaped
E)Trigonal pyramidal

Question 74

What is the molecular shape of BCl₃ as predicted by the VSEPR theory?

A)Linear
B)Trigonal planar
C)Bent
D)Tetrahedral
E)Trigonal pyramidal

Question 75

What is the molecular shape of NH₂Cl as predicted by the VSEPR theory?

A)Trigonal pyramidal
B)Tetrahedral
C)T-shaped
D)See-saw
E)Trigonal planar

Question 76

What is the molecular shape of SiF₆²⁻ as predicted by the VSEPR theory?

A)Trigonal bipyramidal
B)Hexagonal
C)Tetrahedral
D)See-saw
E)Octahedral

Question 77

What is the molecular shape of ClF₂⁻ as predicted by the VSEPR theory?

A)Linear
B)Bent
C)See-saw
D)T-shaped
E)L-shaped

Question 78

Use VSEPR theory to decide which one of the following molecules and ions will have a trigonal pyramidal geometry. (The central atom is always first in the formula.)

A)PCl ₃
B)BF ₃
C)SO ₃
D)BrF ₃
E)CO ₃ ²⁻

Question 79

What is the molecular shape of HOF as predicted by the VSEPR theory?

A)Trigonal pyramidal
B)Trigonal
C)Tetrahedral
D)Linear
E)Bent

Question 80

What is the molecular shape of ClCN as predicted by the VSEPR theory? (Carbon is the central atom.)

A)Linear
B)Bent
C)Angular
D)Trigonal
E)None of these choices are correct.