Question 1

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

Accepted Answer

A) F   F1F1F1S1F1F1F10S   F1F1F1S1F1F1F10Na   F1F1F1S1F1F1F10H 
B) F   F1F1F1S1F1F1F10N   F1F1F1S1F1F1F10P   F1F1F1S1F1F1F10O 
C) N   F1F1F1S1F1F1F10P   F1F1F1S1F1F1F10Si   F1F1F1S1F1F1F10S 
D) F   F1F1F1S1F1F1F10Cl   F1F1F1S1F1F1F10Br   F1F1F1S1F1F1F10C 
E) Te   F1F1F1S1F1F1F10Se   F1F1F1S1F1F1F10S   F1F1F1S1F1F1F10O 
A) F   F1F1F1S1F1F1F10S   F1F1F1S1F1F1F10Na   F1F1F1S1F1F1F10H 
B) F   F1F1F1S1F1F1F10N   F1F1F1S1F1F1F10P   F1F1F1S1F1F1F10O 
C) N   F1F1F1S1F1F1F10P   F1F1F1S1F1F1F10Si   F1F1F1S1F1F1F10S 
D) F   F1F1F1S1F1F1F10Cl   F1F1F1S1F1F1F10Br   F1F1F1S1F1F1F10C 
E) Te   F1F1F1S1F1F1F10Se   F1F1F1S1F1F1F10S   F1F1F1S1F1F1F10O

Question 2

What type of bonding is present in NaCl?

Accepted Answer

A) polar covalent 
B) metallic 
C) ionic 
D) nonpolar covalent 
E) amorphous 
A) polar covalent 
B) metallic 
C) ionic 
D) nonpolar covalent 
E) amorphous

Question 3

Identify the molecule below that contains a double bond.

Accepted Answer

A) HCN 
B) O3 
C) C2H2 
D) S2 
E) N2 
A) HCN 
B) O3 
C) C2H2 
D) S2 
E) N2

Question 4

Which of these statements about greenhouse gases and the greenhouse effect is not correct?
I. Greenhouse gases prevent infrared radiation from escaping through the atmosphere.
II. To absorb infrared radiation, a molecule must have a vibration that produces a change in
The dipole moment of the molecule.
III. Argon is the third most abundant species in the atmosphere (after nitrogen and oxygen),
And therefore is a significant greenhouse gas.
IV. The average amount of carbon dioxide in the atmosphere increases when fossil fuels are
Burned, but not when ethanol (CH3CH2OH) produced from plants is burned.

Accepted Answer

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

Question 5

Which one of the following molecules violates the octet rule?

Accepted Answer

A) SF4 
B) COF2 
C) PBr3 
D) S2Cl2 
E) SiH4 
A) SF4 
B) COF2 
C) PBr3 
D) S2Cl2 
E) SiH4

Question 6

Which of the following double bonds do you predict to be the shortest based on the position of the atoms in the periodic table?

Accepted Answer

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

Question 7

Which of the following bonds is most polar?

Accepted Answer

A) BF1F1F1S1F1F1F10H 
B) NF1F1F1S1F1F1F10H 
C) PF1F1F1S1F1F1F10H 
D) AlF1F1F1S1F1F1F10H 
E) CF1F1F1S1F1F1F10H 
A) BF1F1F1S1F1F1F10H 
B) NF1F1F1S1F1F1F10H 
C) PF1F1F1S1F1F1F10H 
D) AlF1F1F1S1F1F1F10H 
E) CF1F1F1S1F1F1F10H

Question 8

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

Accepted Answer

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

Question 9

Which of the following, based on formal charges, depicts the best Lewis structure for cyanate (NCO-)?

Accepted Answer

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

Question 10

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

Accepted Answer

A) O2 
B) MgO 
C) H2O 
D) CF4 
E) SiO2 
A) O2 
B) MgO 
C) H2O 
D) CF4 
E) SiO2

Question 11

Which of the following compounds is likely to have the weakest H-X bond?

Accepted Answer

A) HF1F1F1S1F1F1F10Br (141 pm) 
B) HF1F1F1S1F1F1F10I (161 pm) 
C) HF1F1F1S1F1F1F10Cl (127 pm) 
D) HF1F1F1S1F1F1F10F (92 pm) 
E) H2S (134 m) 
A) HF1F1F1S1F1F1F10Br (141 pm) 
B) HF1F1F1S1F1F1F10I (161 pm) 
C) HF1F1F1S1F1F1F10Cl (127 pm) 
D) HF1F1F1S1F1F1F10F (92 pm) 
E) H2S (134 m)

Question 12

What is the total number of electrons assigned to the oxygen atom in the Lewis structure of formaldehyde (CH2O)?

Accepted Answer

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

Question 13

Based on the positions of the atoms in the periodic table, arrange the following bonds in order of increasing bond length: HF1F1F1S1F1F1F10H, HF1F1F1S1F1F1F10Br, HF1F1F1S1F1F1F10Cl.

Accepted Answer

HF1F1F1S1F1F1F10H,

Question 14

Hydrogen cyanide (HCN) and hydrogen isocyanide (HNC) have the same elemental composition except H is bonded to carbon in one and to nitrogen in the other. Which statement regarding the Lewis structures of these molecules is not correct?

Accepted Answer

A) Both have 10 valence electrons. 
B) The formal charges are zero for all the atoms in only one of these molecules. 
C) The most electronegative element has a formal charge of F1F1F1S1F1F1F101 in one of these molecules. 
D) The Lewis structures predict that HCN is the more stable molecule. 
E) The formal charges sum to zero in both molecules. 
A) Both have 10 valence electrons. 
B) The formal charges are zero for all the atoms in only one of these molecules. 
C) The most electronegative element has a formal charge of F1F1F1S1F1F1F101 in one of these molecules. 
D) The Lewis structures predict that HCN is the more stable molecule. 
E) The formal charges sum to zero in both molecules.

Question 15

Describe how and why formal charges are used to choose between two possible Lewis structures for a molecule.

Accepted Answer

Formal charges are used to identify the

Question 16

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

Accepted Answer

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

Question 17

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

Accepted Answer

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) 
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 18

Identify which of the following molecules has a bond order of 3: Li2, Be2, N2, F2, C2.

Accepted Answer

Question 19

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

Accepted Answer

A) O2 
B) N2 
C) CNF1F1F1S1F1F1F10 
D) H2 
E) I2 
A) O2 
B) N2 
C) CNF1F1F1S1F1F1F10 
D) H2 
E) I2

Question 20

How many covalent bonds are there in CNF1F1F1S1F1F1F10?

Accepted Answer

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

Exam 8: Chemical Bonds: What Makes a Gas a Greenhouse Gas

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

What type of bonding is present in NaCl?

Identify the molecule below that contains a double bond.

Which one of the following molecules violates the octet rule?

Which of the following double bonds do you predict to be the shortest based on the position of the atoms in the periodic table?

Which of the following bonds is most polar?

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

Which of the following, based on formal charges, depicts the best Lewis structure for cyanate (NCO-)?

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

Which of the following compounds is likely to have the weakest H-X bond?

What is the total number of electrons assigned to the oxygen atom in the Lewis structure of formaldehyde (CH2O)?

Based on the positions of the atoms in the periodic table, arrange the following bonds in order of increasing bond length: HH, HBr, HCl.

Hydrogen cyanide (HCN) and hydrogen isocyanide (HNC) have the same elemental composition except H is bonded to carbon in one and to nitrogen in the other. Which statement regarding the Lewis structures of these molecules is not correct?

Describe how and why formal charges are used to choose between two possible Lewis structures for a molecule.

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

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

Identify which of the following molecules has a bond order of 3: Li2, Be2, N2, F2, C2.

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

How many covalent bonds are there in CN?

Matter and Energy: The Origin of the Universe

Atoms, Ions, and Molecules: Matter Starts Here

Stoichiometry: Mass, Formulas, and Reactions

Solution Chemistry: The Hydrosphere

Thermochemistry: Energy Changes in Reactions

Properties of Gases: The Air We Breathe

A Quantum Model of Atoms: Waves and Particles

Molecular Geometry: Shape Determines Function

Intermolecular Forces: The Uniqueness of Water

Solutions: Properties and Behavior

Solids: Crystals, Alloys, and Polymers

Chemical Kinetics: Reactions in the Atmosphere

Chemical Equilibrium: How Much Product Does a Reaction Really Make

Acidbase Equilibria: Proton Transfer in Biological Systems

Additional Aqueous Equilibria: Chemistry and the Oceans

Thermodynamics: Spontaneous and Nonspontaneous Reactions and Processes

Electrochemistry: The Quest for Clean Energy

Nuclear Chemistry: Applications to Energy and Medicine

Organic and Biological Molecules: the Compounds of Life

The Main Group Elements: Life and the Periodic Table

Transition Metals: Biological and Medical Applications

Filters

Which of the following, based on formal charges, depicts the best Lewis structure for cyanate (NCO^-)?

What is the total number of electrons assigned to the oxygen atom in the Lewis structure of formaldehyde (CH₂O)?

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

Identify which of the following molecules has a bond order of 3: Li₂, Be₂, N₂, F₂, C₂.

How many covalent bonds are there in CN^?