Deck 8: Ionic Versus Covalent Bonding

Question 1

The _____ is a balance between the repulsive interactions between electrons on adjacent ions and the attractive interactions between ions with opposite charges.

Answer 1

total energy of the system

Question 2

Each chemical bond is characterized by a particular optimal internuclear distance called the _____.

Answer 2

bond distance

Question 3

Explain the three features of chemical bonding.

Answer 3

All models of chemical bonding have three features in common:
$\bullet$ Atoms interact with one another to form aggregates such as molecules, compounds, and crystals because doing so lowers the total energy of the system; that is, the aggregates are more stable than the isolated atoms.
$\bullet$ Energy is required to dissociate bonded atoms or ions into isolated atoms or ions. For ionic solids, in which the ions form a three-dimensional array called a lattice, this energy is called the lattice energy (U), the enthalpy change that occurs when a solid ionic compound is transformed into gaseous ions. For covalent compounds, this energy is called the bond energy, which is the enthalpy change that occurs when a given bond in a gaseous molecule is broken.
$\bullet$ Each chemical bond is characterized by a particular optimal internuclear distance called the bond distance (r₀).

Question 4

Energy of the electrostatic attraction (E), a measure of the force's strength, is inversely proportional to the _____between the charged particles, where each ion's charge is represented by the symbol Q.

Question 5

Covalent bonding signifies that positively and negatively charged ions are held together by electrostatic forces.

Question 6

Which of the following best describes lattice energy?

A) It is the enthalpy change that occurs when a solid ionic compound is transformed into gaseous ions.
B) It is the enthalpy change that occurs in covalent compounds when a given bond in a gaseous molecule is broken.
C) It is the enthalpy change that occurs when a specified amount of solute is dissolved in a given quantity of solvent.
D) It is the enthalpy change that occurs when 1 mol of a substance is melted.
E) It is the enthalpy change that occurs during a combustion reaction.

Question 7

Ions cannot be infinitely close together.

Question 8

Which of the following best describes covalent bonding?

A) It is a type of chemical bonding exhibited in compounds that contain positively and negatively charged ions.
B) It is a type of chemical bonding exhibited in compounds that dissolve in aqueous solutions and conduct electricity.
C) It is a type of chemical bonding exhibited in nonvolatile compounds.
D) It is a type of chemical bonding in which electrons are shared between atoms in a molecule or a polyatomic ion.
E) It is a type of chemical bonding in which the charged particles are held together by the electromagnetic forces.

Question 9

Explain the significance of the energy of the electrostatic attraction.

Question 10

The enthalpy change that occurs when a given bond in a gaseous molecule is broken is known as bond _____.

A) strength
B) distance
C) order
D) energy
E) length

Question 11

_____ is a type of bonding in which positively and negatively charged ions are held together by electrostatic forces.

Question 12

The energy of the electrostatic attraction (E), a measure of the force's strength, is inversely proportional to _____.

A) the internuclear distance between the charged particles
B) the sum of the charges on the ions
C) the product of the charges on the ions
D) Avogadro's number
E) the difference of the charges on the ions

Question 13

What is the amount of energy released when 1 mol of a gaseous compound with charges of +1.00 on the cation and -1.00 on the anion is formed? Assume the internuclear distance in the gas phase as 185 pm.

A) 845 kJ/mol
B) 693 kJ/mol
C) 548 kJ/mol
D) 752 kJ/mol
E) 476 kJ/mol

Question 14

The energy of the electrostatic attraction between two is inversely proportional to their respective charges.

Question 15

What is the amount of energy released when 1 mol of a gaseous compound with charges of +3.000 on the cation and -1.000 on the anion is formed? Assume the internuclear distance in the gas phase as 215.0 pm.

A) 1574 kJ/mol
B) 1941 kJ/mol
C) 1894 kJ/mol
D) 1688 kJ/mol
E) 1736 kJ/mol

Question 16

Sugar and salt are white crystalline compounds with very different bonding characteristics. How can the two compounds be differentiated based on the type of bonds they contain?

Question 17

A system consisting of separate ion pairs is more stable than an ionic lattice.

Question 18

Energy is required to disassociate bonded atoms or ions into isolated atoms or ions.

Question 19

Energy is absorbed when a bond is formed.

Question 20

Isolated atoms are more stable than the aggregated atoms.

Question 21

Lattice energy is directly proportional to the size of the ions.

Question 22

Lattice energies are the lowest for substances with small, highly charged ions.

Question 23

The position of the atoms is different in the various resonance structures of a compound.

Question 24

Hydrogen, with only two valence electrons, obeys the octet rule.

Question 25

_____ is the temperature at which the individual ions in a lattice or the individual molecules in a covalent compound have enough kinetic energy to overcome the attractive forces that hold them in place in the solid.

Question 26

Explain the relationship between lattice energies and physical properties.

Question 27

Which of the following compounds has the lowest lattice energy?

A) Ca(OH)₂
B) KBr
C) InAs
D) ZnS
E) SrSe

Question 28

The tendency for atoms to lose, gain, or share electrons to reach a total of eight valence electrons is known as the _____.

A) Frenkel defect
B) octet rule
C) band theory
D) aufbau principle
E) Meissner effect

Question 29

The number of dots in the Lewis dot symbol is the same as the number of valence electrons.

Question 30

If an atom has the number of bonds typical for that atom, its formal charge is zero.

Question 31

Which of the following feature is true of lattice energy?

A) It depends on the product of the charges on the ions.
B) It depends on the difference of the charges on the ions.
C) It is directly proportional to the internuclear distance of the ions.
D) It is directly proportional to the size of the ions.
E) It is inversely proportional to the sum of the charges of the ions.

Question 32

A thermochemical cycle that describes the process in which an ionic solid is conceptually formed from its component elements in a stepwise manner is known as the _____ cycle.

A) Tyndall
B) Graham
C) Born-Haber
D) Boyle
E) Henry

Question 33

The number of dots in an element's Lewis dot symbol is the same as the number of its _____.

Question 34

Which of the following compounds has the highest lattice energy?

A) GaP
B) CaO
C) BaS
D) RbCl
E) HCl

Question 35

The Lewis structure with the set of formal charges closest to zero is the most unstable.

Question 36

Explain the Lewis electron dot symbols.

Question 37

_____ are used for predicting the number of bonds formed by most elements in their compounds.

Question 38

Which of the following is used to predict the number of bonds formed by most elements in their compounds?

A) Van der Waals forces
B) Aufbau principle
C) Boltzmann distribution
D) Lewis electron dot symbols
E) Bragg equation

Question 39

The octet rule indicates that atoms tend to lose, gain, or share electrons to reach a total of six valence electrons.

Question 40

Lattice energy is the most important factor in determining the stability of a(n) _____ compound.

Question 41

Mention the exceptions to the octet rule.

Question 42

All Brønsted-Lowry bases are electron-pair donors.

Question 43

The electron pair being shared by atoms is called a(n) _____ pair.

A) homogenous
B) bonding
C) ionic
D) lone
E) neutral

Question 44

Which of the following is true of a formal charge?

A) It represents a true charge on an atom in a covalent bond.
B) If an atom has the number of bonds typical for that atom, its formal charge is greater than one.
C) The sum of the formal charges on the atoms within a molecule or an ion must be less than the overall charge on the molecule or ion.
D) The Lewis structure with the set of formal charges closest to zero is usually the most unstable.
E) It predicts the most likely structure when a compound has more than one valid Lewis structure.

Question 45

In Lewis electron structures, _____ pairs are not shared between atoms.

Question 46

A(n) _____ is a Lewis electron structure that has different arrangements of electrons around atoms whose positions do not change.

Question 47

Electron-deficient molecules are Lewis bases.

Question 48

_____ molecules are those which have less than an octet of electrons around one atom.

Question 49

BCl₃ follows the octet rule.

Question 50

Electron-deficient compounds have a strong tendency to gain electrons in their reactions.

Question 51

Explain formal charges.

Question 52

A Lewis structure cannot be drawn for NO because it:

A) is made up of s-block and p-block elements.
B) is made up of only s-block elements.
C) it has an odd number of valence electrons.
D) shares more than two electron pairs.
E) has an even number of valence electrons.

Question 53

In the oxoanions of the heavier p-block elements, the central atom often has an expanded valence shell.

Question 54

Compounds with more than an octet of electrons around an atom are called _____.

A) polar covalent bonds
B) amphoteric bonds
C) adducts
D) expanded-valence molecules
E) resonance structures

Question 55

Which of the following is the Lewis structure of CO₂?

A)
B)
C)
D)
E)

Question 56

Which of the following is used to compute a formal charge?

A) $\frac { 1 } { 2 } m v ^ { 2 }$
B) $k \frac { Q _ { 1 } Q _ { 2 } } { r }$
C) $k \frac { r } { Q _ { 1 } Q _ { 2 } }$
D) $\text { valence } e ^ { - } - \left( \text {nonbonding } e ^ { - } + \frac { \text { bonding } e ^ { - } } { 2 } \right)$
E) $Q r$

Question 57

Which of the following does not have a single Lewis structure?

A) H₂O
B) Cl₂
C) NH₄⁺
D) CH₂O
E) O₃

Question 58

Which of the following compounds is an exception to the octet rule?

A) H₂O
B) CO₂
C) NH₃
D) CH₂O
E) SF₆

Question 59

Given: The Lewis structure of BeCl₂. The structure shown above is an exception to the octet rule because the arrangement:

A) does not contain any double bonds.
B) gives each chlorine atom only eight electrons.
C) contains a beryllium atom.
D) contains only two chlorine atoms.
E) gives beryllium only four electrons.

Question 60

What is the formal charge of boron in BH₃?

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

Question 61

If the bonds in the products are stronger than those in the reactants, the reaction is exothermic.

Question 62

Which of the following has the lowest bond strength?

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

Question 63

There is a direct correlation between electronegativity and bond polarity.

Question 64

Bonds between hydrogen and atoms in the same column of the periodic table decrease in strength as we go down the column. Thus, an H-F bond is _____ than an H-I bond.

Question 65

In the reaction (CH₃)₂O + BF₃ → (CH₃)₂O:BF₃, the Lewis acid is _____.

A) O:BF₃
B) (CH₃)₂O
C) (CH₃)₂O:BF₃
D) (CH₃)₂
E) BF₃

Question 66

In a polar covalent bond, the:

A) ions are held together by electrostatic forces.
B) electrons are shared unequally between the atoms.
C) protons hold the compound's component elements together.
D) number of protons exceed the number of electrons.
E) atomic numbers of component elements exceed their own mass numbers.

Question 67

Triple bonds between like atoms are longer than double bonds.

Question 68

The asymmetrical charge distribution in a polar substance produces a dipole moment.

Question 69

Which of the following has the greatest bond strength?

A) H-I
B) H-At
C) H-Br
D) H-F
E) H-Cl

Question 70

Differentiate between a Lewis acid and a Lewis base. Explain how it differs from the Bronsted-Lowry concept of acids and bases.

Question 71

The bond formed between a Lewis acid and a Lewis base is a coordinate covalent bond.

Question 72

As bond orders increase, bond lengths generally decrease.

Question 73

In the reaction H₂O + SO₃ → H₂SO₄, the Lewis base is _____.

A) H₂SO₄
B) SO₃
C) H₂O
D) SO₄^2-
E) H⁺

Question 74

What is an adduct?

A) It is the optimal internuclear distance between two bonded atoms.
B) It is the product of reaction between a Lewis acid and a Lewis base with a coordinate covalent bond.
C) It is any species that can donate a pair of electrons.
D) It is any species that can accept a pair of electrons.
E) It is the enthalpy change that occurs when a solid ionic compound is transformed into gaseous ions.

Question 75

A bond is polar if the bonded atoms have equal electronegativities.

Question 76

Any species that can accept a pair of electrons are known as _____.

Question 77

Bonds between like atoms usually become weaker as we go down a column. Thus, the C-C single bond is _____ than the Si-Si single bond.

Question 78

Explain the relationship between bond order and bond energy.

Question 79

The bond energy of a C-H single bond is the same in all organic compounds.

Question 80

Which of the following is true of bond polarity?

A) A bond is nonpolar if the electronegativities of the bonded atoms are unequal.
B) The bond polarity decreases with an increasing difference in electronegativity.
C) A bond is polar if the bonded atoms have equal electronegativities.
D) The ionic character increases with an increasing difference in electronegativity.
E) There is no direct correlation between electronegativity and bond polarity.