Deck 4: Covalent Compounds

Question 1

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.

A)180°
B)120°
C)109.5°
D)90°
E)60°

Answer 1

B

Question 2

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

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

Answer 2

B

Question 3

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

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

Answer 3

B

Question 4

A diatomic molecule contains I. atoms of two different elements bonded together with a covalent bond.
II. two atoms of the same element bonded together with a covalent bond.
III. two lone pairs of electrons.

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

Question 5

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

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

Question 6

Which bond is the most polar?

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

Question 7

What are the bond angles in a tetrahedral geometry?

A)180°
B)120°
C)109.5°
D)90°
E)60°

Question 8

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

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

Question 9

Aspartic acid is an amino acid used to synthesize proteins. How many polar bonds are in the aspartic acid structure shown below?

A)4
B)6
C)9
D)12
E)15

Question 10

Which of the statements concerning chemical bonds is false?

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 11

How many covalent bonds are generally formed by atoms with five valence electrons?

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

Question 12

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

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

Question 13

What is the molecular shape around the phosphorus atom in PH₃?

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

Question 14

What is the Lewis structure for chloroethylene (C₂H₃Cl)?

A)
B)
C)
D)

Question 15

Which atom has the lowest electronegativity?

A)Al
B)S
C)Se
D)Rb
E)F

Question 16

Which bond is the least polar?

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

Question 17

Which of the following molecule(s)is(are)polar?

A)CO₂
B)CH₄
C)CBr₄
D)CHBr₃
E)More than one of the above molecules are polar.

Question 18

Covalent bonds result from the _____ electrons between two atoms.

A)transfer of
B)equal sharing of
C)unequal sharing of
D)A, B, and C are correct
E)B and C are correct

Question 19

Aspartic acid is an amino acid used to synthesize proteins. How many lone pairs of electrons need to be added to complete the aspartic acid structure shown below?

A)4
B)6
C)8
D)9
E)11

Question 20

What is another name for an unshared pair of electrons in a covalent compound?

A)lone pair of electrons
B)nonbonded electron pair
C)bonding pair of electrons
D)lone pair of electrons or nonbonded electron pair

Question 21

Which is the correct Lewis structure for OBr^-?

A)
B)
C)
D)
E)

Question 22

Which statement concerning chemical bonds is false?

A)A covalent bond involves the sharing of electrons between two nonmetal atoms.
B)An ionic bond is the attraction between oppositely charged ions.
C)A nonpolar bond is a covalent bond in which electrons are not shared equally between the atoms.
D)Electronegativity is a measure of the attraction an atom has for the electrons it shares in a bond.

Question 23

What is the chemical formula for dinitrogen tetroxide?

A)N₄O₂
B)O₄N₂
C)N₂O₄
D)O₂N₄
E)NO₂

Question 24

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

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

Question 25

Estimate the bond angles around the sulfur atom in the structure shown below.

A)90°
B)109.5°
C)120°
D)180°

Question 26

Which of the statements concerning compounds is incorrect?

A)Compounds are formed when atoms of two or more different elements are chemically bonded.
B)Ionic compounds are composed of cations and anions.
C)Covalent compounds are composed of metals and nonmetals.
D)Covalent compounds are composed of individual molecules.

Question 27

Which of the following is classified as a group in the valence shell electron pair repulsion (VSEPR)theory?

A)an atom
B)a lone pair of electrons
C)a valence electron
D)either an atom or a valence electron
E)either an atom or a lone pair of electrons

Question 28

Which bond has the polarity incorrectly labeled?

A) ^{$\delta$ +} H-Cl ^{$\delta$ -}
B) ^{$\delta$ +} O-C ^{$\delta$ -}
C) 1 ^{$\delta$ +} Cl- ^{$\delta$ -}
D) ^{$\delta$ -} Cl-Br ^{$\delta$ +}
E) ^{$\delta$ -} F-O ^{$\delta$ +}

Question 29

What is the total number of bonding electrons in the structure below?

A)5
B)10
C)20
D)30

Question 30

Which atom(s)in the structure below has(have)a partial negative charge ( $\delta$ ^-)?

A)carbon
B)fluorine
C)hydrogen
D)nitrogen
E)nitrogen and fluorine

Question 31

Which molecule's Lewis structure contains an atom that violates the octet rule?

A)H₂O
B)BeH₂
C)PCl₃
D)H₂Se

Question 32

What is the molecular shape around the oxygen atom in the structure shown below?

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

Question 33

What is the molecular shape around the nitrogen atom in the structure shown below?

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

Question 34

Which element may have more than eight valence electrons around it when present in a covalent compound?

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

Question 35

How many lone pairs of electrons need to be added to the Lewis structure of carbonic acid shown below?

A)0
B)3
C)4
D)6
E)7

Question 36

What is the correct chemical formula of selenium dioxide?

A)SO₂
B)SeO₂
C)Se₂O
D)OS₂

Question 37

Which Lewis structure is incorrect?

A)
B)
C)
D)

Question 38

Which molecule or ion has only two resonance structures to describe its bonding?

A)CO₃^2-
B)NO₃^-
C)HCO₃^1-
D)SO₃

Question 39

Which compound has the greatest number of valence electrons?

A)H₂S
B)CH₄
C)NH₃
D)H₂O
E)All of the molecules above have the same number of valence electrons.

Question 40

The Lewis structure shown below is not a valid Lewis structure. What statement best describes the error in the structure?

A)The nitrogen atoms violate the octet rule.
B)The chlorine atoms violate the octet rule.
C)The structure contains an incorrect number of valence electrons.
D)Chlorine atoms and nitrogen atoms do not typically form bonds with each other.

Question 41

Bonding is the joining of two atoms in a stable arrangement.

Question 42

A molecule is a discrete group of atoms held together by covalent bonds.

Question 43

Resonance structures for a substance differ only in the location of multiple bonds and the position of lone electron pairs.

Question 44

Phosphorus usually forms two covalent bonds in a molecule.

Question 45

Nonpolar molecules may contain polar bonds.

Question 46

Unequal sharing of electrons in a covalent bond results in a polar bond.

Question 47

The covalent bond between chlorine and iodine is a polar one. Which of the following properly represents the direction of polarity in this bond?

A) ^{$\delta$ +} Cl-I ^{$\delta$ -}
B) ^{$\delta$ -} Cl-I ^{$\delta$ +}
C)⁺ Cl-I ^-
D)^- Cl-I ⁺

Question 48

Atoms with seven valence electrons typically form one covalent bond.

Question 49

The Lewis structure for BH₃ contains an atom that does not follow the octet rule.

Question 50

Some covalent compounds are solids, some are liquids, and some are gases at room temperature.

Question 51

The Lewis structure for PH₃ contains an atom that does not follow the octet rule.

Question 52

A Lewis structure shows the connectivity between atoms in a molecule, as well as where all the bonding and nonbonding valence electrons reside.

Question 53

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

Question 54

The formula for dinitrogen pentoxide is N₅O₂.

Question 55

The correct name for SF₆ is sulfur heptafluoride.

Question 56

There can be a no more than two resonance structures for a molecule.

Question 57

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

Question 58

The Lewis structure of formaldehyde is shown below. Which statement concerning this structure is incorrect?

A)Two electrons are being shared between the carbon atom and the oxygen atom.
B)The oxygen atom has four valence electrons that are not being shared with another atom.
C)The oxygen and carbon atoms each have an octet of electrons in their valence shells.
D)The hydrogen atoms have filled valence shells.

Question 59

Atoms with three valence electrons generally form five bonds.

Question 60

A bond formed between the elements hydrogen and bromine would be considered an ionic bond.

Question 61

A double bond is counted as two groups in the valence shell electron pair repulsion (VSEPR)theory.

Question 62

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

Question 63

Dibromomethane (CH₂Br₂)is a nonpolar molecule.

Question 64

The Lewis structure for the molecule below is incomplete because it is missing six pairs of nonbonding electrons.

Question 65

The symbol $\delta$ ^- is given to the more electronegative atom in a polar bond.

Question 66

The structures shown below are resonance structures of sulfur dioxide. and

Question 67

The shapes around the left and right carbon atoms in the structure below are tetrahedral and linear, respectively.

Question 68

The shape around each carbon atom in the molecule below is trigonal planar.

Question 69

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

Question 70

The structures shown below are resonance structures of sulfur dioxide. and

Question 71

A N-O bond is more polar than a P-O bond.

Question 72

In the valence shell electron pair repulsion (VSEPR)theory, a group is defined as an atom or a lone pair of electrons.

Question 73

When writing Lewis structures, the symbol below is placed between resonance structures.

Question 74

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

Question 75

The molecule below is a polar molecule.

Question 76

Ethane (C₂H₆)is a polar molecule.

Question 77

A bond between a carbon atom and a nitrogen atom is a polar covalent bond.

Question 78

Double bonds and triple bonds are never polar bonds.

Question 79

C-H bonds are considered to be nonpolar, because the electronegativity difference between carbon and hydrogen is small.

Question 80

The molecule below is a polar molecule.