Question 1

Identify the diatomic element from the given choices.

Accepted Answer

A) Chlorine 
B) Carbon 
C) Boron 
D) Sulfur 
E) Lithium 
A) Chlorine 
B) Carbon 
C) Boron 
D) Sulfur 
E) Lithium A

Question 2

How many valence electrons are in a molecule of formaldehyde (CH2O)?

Accepted Answer

A) 16 
B) 12 
C) 10 
D) 8 
E) 0 
A) 16 
B) 12 
C) 10 
D) 8 
E) 0 B

Question 3

Considering the electronegativity values indicated for each element,which covalent bond has the LEAST degree of polarity?

Accepted Answer

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

Question 4

The molecule below is a polar molecule.

Accepted Answer

A) True 
 B)False

Question 5

A double bond consists of four electrons shared between two atoms.

Accepted Answer

A) True 
 B)False

Question 6

Predict the bond angles around the carbon atom in the structure of carbonic acid shown below. Don't forget to draw in lone pairs where needed to give octets.

Accepted Answer

A) 180° 
B) 120° 
C) 109.5° 
D) 90° 
E) 60° 
A) 180° 
B) 120° 
C) 109.5° 
D) 90° 
E) 60°

Question 7

Rank the atoms Br,Cl,and F in order of increasing electronegativity.

Accepted Answer

A) F < Br < Cl 
B) Cl < Br < F 
C) Br < Cl < F 
D) F < Cl < Br 
E) Cl < F < Br 
A) F < Br < Cl 
B) Cl < Br < F 
C) Br < Cl < F 
D) F < Cl < Br 
E) Cl < F < Br

Question 8

What is the chemical formula for dinitrogen tetroxide?

Accepted Answer

A) N4O2 
B) O4N2 
C) N2O4 
D) O2N4 
E) NO2 
A) N4O2 
B) O4N2 
C) N2O4 
D) O2N4 
E) NO2

Question 9

The chemical formula for phosphorus pentachloride is ________.

Accepted Answer

The answer of The chemical formula for phosphorus pentachloride is...

Question 10

How many lone pairs of electrons are present in the Lewis structure of ammonia,NH3?

Accepted Answer

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

Question 11

The molecular shape around the boron atom in BCl3 is different than the molecular shape around the nitrogen atom in NCl3.

Accepted Answer

A) True 
 B)False

Question 12

Which of the following compounds is classified as covalent?

Accepted Answer

A) KCl 
B) LiBr 
C) HCl 
D) NaBr 
E) None of the choices are correct. 
A) KCl 
B) LiBr 
C) HCl 
D) NaBr 
E) None of the choices are correct.

Question 13

Every atom must have an octet of electrons in order for a Lewis structure to be considered valid.

Accepted Answer

A) True 
 B)False

Question 14

Which of the statements concerning chemical bonds is false?

Accepted Answer

A) The sharing of electrons between two nonmetal atoms results in a covalent bond. 
B) The attraction between oppositely charged ions results in an ionic bond. 
C) The term nonpolar is used to describe a covalent bond in which electrons are not shared equally. 
D) A bond dipole is the separation of charge that results when atoms sharing electrons have different electronegativities. 
A) The sharing of electrons between two nonmetal atoms results in a covalent bond. 
B) The attraction between oppositely charged ions results in an ionic bond. 
C) The term nonpolar is used to describe a covalent bond in which electrons are not shared equally. 
D) A bond dipole is the separation of charge that results when atoms sharing electrons have different electronegativities.

Question 15

Ethane (C2H6)is a polar molecule.

Accepted Answer

A) True 
 B)False

Question 16

A resonance hybrid is a composite of all resonance structures that spreads out electron pairs in multiple bonds and lone pairs.

Accepted Answer

A) True 
 B)False

Question 17

How many nonbonded electron pairs are in the Lewis structure below?

Accepted Answer

A) 2 
B) 4 
C) 6 
D) 8 
E) 16 
A) 2 
B) 4 
C) 6 
D) 8 
E) 16

Question 18

In Lewis structures,fluorine atoms generally do not obey the octet rule.

Accepted Answer

A) True 
 B)False

Question 19

A molecule that contains only one polar bond is a polar molecule.

Accepted Answer

A) True 
 B)False

Question 20

Phosphorus usually forms two covalent bonds in a molecule.

Accepted Answer

A) True 
 B)False

Exam 4: Covalent Compounds

Identify the diatomic element from the given choices.

How many valence electrons are in a molecule of formaldehyde (CH2O)?

Considering the electronegativity values indicated for each element,which covalent bond has the LEAST degree of polarity?

The molecule below is a polar molecule.

A double bond consists of four electrons shared between two atoms.

Predict the bond angles around the carbon atom in the structure of carbonic acid shown below. Don't forget to draw in lone pairs where needed to give octets.

Rank the atoms Br,Cl,and F in order of increasing electronegativity.

What is the chemical formula for dinitrogen tetroxide?

The chemical formula for phosphorus pentachloride is ________.

How many lone pairs of electrons are present in the Lewis structure of ammonia,NH3?

The molecular shape around the boron atom in BCl3 is different than the molecular shape around the nitrogen atom in NCl3.

Which of the following compounds is classified as covalent?

Every atom must have an octet of electrons in order for a Lewis structure to be considered valid.

Which of the statements concerning chemical bonds is false?

Ethane (C2H6)is a polar molecule.

A resonance hybrid is a composite of all resonance structures that spreads out electron pairs in multiple bonds and lone pairs.

How many nonbonded electron pairs are in the Lewis structure below?

In Lewis structures,fluorine atoms generally do not obey the octet rule.

A molecule that contains only one polar bond is a polar molecule.

Phosphorus usually forms two covalent bonds in a molecule.

Matter and Measurement

Atoms and the Periodic Table

Ionic Compounds

Chemical Reactions

Energy Changes,reaction Rates,and Equilibrium

Gases,liquids,and Solids

Solutions

Acids and Bases

Nuclear Chemistry

Introduction to Organic Molecules and Functional Groups

Alkanes

Unsaturated Hydrocarbons

Organic Compounds That Contain Oxygen,halogen,or Sulfur

The Three-Dimensional Shape of Molecules

Aldehydes and Ketones

Carboxylic Acids,esters,and Amides

Amines and Neurotransmitters

Lipids

Carbohydrates

Amino Acids,proteins,and Enzymes

Nucleic Acids and Protein Synthesis

Metabolism and Energy Production

Carbohydrate,lipid,and Protein Metabolism

Filters

How many valence electrons are in a molecule of formaldehyde (CH₂O)?

How many lone pairs of electrons are present in the Lewis structure of ammonia,NH₃?

The molecular shape around the boron atom in BCl₃ is different than the molecular shape around the nitrogen atom in NCl₃.

Ethane (C₂H₆)is a polar molecule.