Deck 9: Models of Chemical Bonding

Question 1

For which of the following elements (in their normal, stable, forms) would it be correct to describe the bonding as involving "electron pooling"?

A) hydrogen
B) helium
C) sulfur
D) iodine
E) aluminum

Answer 1

aluminum

Question 2

A Born-Haber cycle applied to the formation reaction of an ionic solid

A) is normally used to calculate ionization energy.
B) is normally used to calculate electron affinity.
C) is normally used to calculate bond energy.
D) is normally used to determine the overall enthalpy change.
E) is an application of Hess's Law.

Answer 2

is an application of Hess's Law.

Question 3

Select the correct formula for a compound formed from calcium and chlorine.

A) CaCl
B) CaCl₂
C) Ca₂Cl
D) Ca₂Cl₂
E) CaCl₃

Answer 3

CaCl₂

Question 4

Select the element whose Lewis symbol is correct.

A)
B)
C)
D)
E)

Question 5

Select the compound with the lowest (i.e., least negative) lattice energy.

A) CsBr(s)
B) NaCl(s)
C) SrO(s)
D) CaO(s)
E) KBr(s)

Question 6

Calculate the lattice energy of magnesium sulfide from the data given below. Mg(s) $\rightarrow$ Mg(g) ?H $\degree$ = 148 kJ/mol
Mg(g) $\rightarrow$ Mg²⁺(g) + 2e¯ ?H $\degree$ = 2186 kJ/mol
S₈(s) $\rightarrow$ 8S(g) ?H $\degree$ = 2232 kJ/mol
S(g) + 2e¯ $\rightarrow$ S²¯(g) ?H $\degree$ = 450 kJ/mol
8Mg(s) + S₈(s) $\rightarrow$ 8MgS(s) ?H $\degree$ = -2744 kJ/mol
Mg²⁺(g) + S²¯(g) $\rightarrow$ MgS(s) ?H $\degree$ _lattice = ?

A) -3406 kJ/mol
B) -2720. kJ/mol
C) 2720. kJ/mol
D) 3406 kJ/mol
E) None of these choices is correct.

Question 7

The lattice energy for ionic crystals increases as the charge on the ions _____________ and the size of the ions __________________ .

A) increases, increases
B) increases, decreases
C) decreases, increases
D) decreases, decreases
E) None of these choices is generally correct.

Question 8

Which of the following is a covalent compound?

A) Na₂O
B) CaCl₂
C) Cl₂O
D) CsCl
E) Al₂O₃

Question 9

Analysis of an unknown substance showed that it has a high boiling point and is brittle. It is an insulator as a solid but conducts electricity when melted. Which of the following substances would have those characteristics?

A) HCl
B) Al
C) KBr
D) SiF₄
E) I₂

Question 10

Which of the following is an ionic compound?

A) H₂S
B) NH₃
C) I₂
D) KI
E) CCl₄

Question 11

Which of the following contains covalent bonds?

A) BaO
B) IBr
C) Mg
D) LiBr
E) Cu

Question 12

Select the element whose Lewis symbol is correct.

A)
B)
C)
D)
E)

Question 13

Select the correct formula for a compound formed from barium and nitrogen.

A) BaN
B) BaN₂
C) Ba₂N₃
D) Ba₂N
E) Ba₃N₂

Question 14

Select the compound with the highest (i.e., most negative) lattice energy.

A) CaS(s)
B) BaO(s)
C) NaI(s)
D) LiBr(s)
E) MgO(s)

Question 15

Which one of the following properties is least characteristic of typical ionic compounds?

A) high melting point
B) high boiling point
C) brittleness
D) poor electrical conductor when solid
E) poor electrical conductor when molten

Question 16

In which of these substances are the atoms held together by metallic bonding?

A) CO₂
B) Si
C) Br₂
D) S₈
E) Cr

Question 17

In which of these substances are the atoms held together by polar covalent bonding?

A) SrCl₂
B) CsCl
C) ClF
D) TiF₂
E) S₈

Question 18

The diameter of a chloride ion is 362 pm, and the diameter of a potassium ion is 276 pm. What is the distance between the nuclei of adjacent chloride and potassium ions in solid potassium chloride?

A) 1276 pm
B) 638 pm
C) 319 pm
D) 181 pm
E) 138 pm

Question 19

The lattice energy of MgCl₂ is the energy change for which one of the following processes?

A) Mg(s) + Cl₂(g) $\rightarrow$ MgCl₂(s)
B) Mg(g) + 2Cl(g) $\rightarrow$ MgCl₂(s)
C) Mg²⁺(s) + 2Cl¯(g) $\rightarrow$ MgCl₂(g)
D) Mg²⁺(g) + 2Cl¯(g) $\rightarrow$ MgCl₂(s)
E) MgCl₂(aq) $\rightarrow$ MgCl₂(s)

Question 20

The lattice energy of CaF₂ is the energy change for which one, if any, of the following processes?

A) Ca²⁺(s) + 2F¯(g) $\rightarrow$ CaF₂(g)
B) CaF₂(g) $\rightarrow$ CaF₂(s)
C) Ca(g) + 2F(g) $\rightarrow$ CaF₂(s)
D) CaF₂(aq) $\rightarrow$ CaF₂(s)
E) None of these choices is correct.

Question 21

Which one of the following properties is least characteristic of substances composed of small, covalently-bonded molecules?

A) low melting point
B) low boiling point
C) weak bonds
D) poor electrical conductor when solid
E) poor electrical conductor when molten

Question 22

Based on electronegativity trends in the periodic table, predict which of the following compounds will have the greatest % ionic character in its bonds.

A) H₂O
B) LiI
C) CaO
D) RbF
E) HCl

Question 23

Arrange aluminum, nitrogen, phosphorus and indium in order of increasing electronegativity.

A) Al < In < N < P
B) Al < In < P < N
C) In < Al < P < N
D) In < P < Al < N
E) None of these choices is correct.

Question 24

Quartz (SiO₂) is a solid with a melting point of 1550 $\degree$ C. The bonding in quartz is best described as

A) lattice energy.
B) network attractions.
C) ionic bonding.
D) covalent bonding.
E) metallic bonding.

Question 25

Select the strongest bond in the following group.

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

Question 26

Which of the following period 3 chlorides would be expected to have the highest melting point?

A) MgCl₂
B) AlCl₃
C) SiCl₄
D) PCl₃
E) SCl₂

Question 27

Combustion of a fat will release more energy than combustion of an equal mass of carbohydrate because

A) fats contain more bonds to oxygen than carbohydrates.
B) fats contain fewer bonds to oxygen than carbohydrates.
C) the total energy of the carbon-carbon and carbon-hydrogen bonds in fats is greater than the energy content of the carbon-oxygen and oxygen-hydrogen bonds in the reaction products (carbon dioxide and water).
D) the total energy of the carbon-carbon and carbon-hydrogen bonds in fats is greater than the energy content of the bonds in carbohydrates.
E) fats have higher molar masses than carbohydrates.

Question 28

Acetone can be easily converted to isopropyl alcohol by addition of hydrogen to the carbon-oxygen double bond. Calculate the enthalpy of reaction using the bond energies given.

A) -484 kJ
B) -366 kJ
C) -48 kJ
D) +48 kJ
E) +366 kJ

Question 29

Electronegativity is a measure of

A) the energy needed to remove an electron from an atom.
B) the energy released when an electron is added to an atom.
C) the magnitude of the negative charge on an electron.
D) the attraction by an atom for electrons in a chemical bond.
E) the magnitude of the negative charge on a molecule.

Question 30

Which of the following elements is the most electronegative?

A) Ne
B) Rb
C) P
D) I
E) Cl

Question 31

Using the bond energies provided below, calculate ?H $\degree$ for the reaction Bond energies: C H = 413 kJ/mol, Cl Cl = 243 kJ/mol, C Cl = 339 kJ/mol, H Cl = 427 kJ/mol

A) 1422 kJ
B) 440 kJ
C) 110 kJ
D) -110 kJ
E) -440 kJ

Question 32

Nitrogen and hydrogen combine to form ammonia in the Haber process. Calculate (in kJ) the standard enthalpy change ?H $\degree$ for the reaction written below, using the bond energies given.

A) -969 kJ
B) -204 kJ
C) -105 kJ
D) 204 kJ
E) 595 kJ

Question 33

Arrange the following bonds in order of increasing bond strength.

A) C I < C
Br < C
Cl < C
F
B) C F < C
Cl < C
Br < C
I
C) C Br < C
I < C
Cl < C
F
D) C I < C
Br < C
F< C
Cl
E) None of these choices is correct.

Question 34

When two atoms form a covalently-bonded diatomic molecule, the distance between the nuclei at which the potential energy is at a minimum is called

A) the bond energy.
B) the bond length.
C) the molecular diameter.
D) the covalent radius.
E) the covalent diameter.

Question 35

Arrange oxygen, sulfur, calcium, rubidium and potassium in order of decreasing electronegativity.

A) O > S > Ca > K > Rb
B) O > S > Ca > Rb > K
C) O > S > Rb > K > Ca
D) O > S > Rb > Ca > K
E) None of these choices is correct.

Question 36

Which of the following elements is the least electronegative?

A) Si
B) Se
C) S
D) Sc
E) Sr

Question 37

Arrange calcium, rubidium, sulfur, and arsenic in order of decreasing electronegativity.

A) S > As > Rb > Ca
B) S > As > Ca > Rb
C) As > S > Rb > Ca
D) As > S > Ca > Rb
E) None of these choices is correct.

Question 38

When one mole of each of the following liquids is burned, which will produce the most heat energy?

A) C₆H₁₄
B) C₅H₁₂
C) C₆H₁₄O
D) C₆H₁₂O
E) C₆H₁₀O₃

Question 39

Hydrogenation of double and triple bonds is an important industrial process. Calculate (in kJ) the standard enthalpy change ?H $\degree$ for the hydrogenation of ethyne (acetylene) to ethane.

A) -296 kJ
B) -51 kJ
C) 51 kJ
D) 296 kJ
E) 381 kJ

Question 40

Which of the following elements is the most electronegative?

A) S
B) Ru
C) Si
D) Te
E) Cs

Question 41

Using appropriate, real examples to illustrate your answer, describe the correlation between bond energy and bond length for a series of varying bond order.

Question 42

In not more than three sentences, describe the electron arrangement responsible for bonding in Cl₂ molecules.

Question 43

The majority of elements are good electrical conductors when in solid form.

Question 44

Covalent bonding typically occurs when a ______________ bonds with a ______________.

Question 45

When an atom is represented in a Lewis electron dot symbol, the element symbol represents the ______________ and the dots represent the ______________.

Question 46

Most of the copper sold in major metal markets is highly purified, typically to 99.99%. Why is this?

Question 47

Using appropriate, real examples to illustrate your answer, describe the correlation between bond energy and bond length for a series of single bonds.

Question 48

In not more than three sentences, describe the electron arrangement responsible for bonding in solid SrCl₂.

Question 49

Which one of the following properties is least characteristic of typical metals?

A) moderately high melting point
B) high boiling point
C) brittleness
D) good electrical conductor when solid
E) good electrical conductor when molten

Question 50

Select the most polar bond amongst the following.

A) C O
B) Si F
C) Cl F
D) C F
E) C I

Question 51

Ionic bonding typically occurs when a ______________ bonds with a ______________.

Question 52

Describe in brief how electronegativity values can be used to predict the percent ionic character of a bond between two atoms.

Question 53

The lattice energy of rubidium chloride is the energy change accompanying the process
Rb⁺(g) + Cl^-(g) $\rightarrow$ RbCl(s)
Calculate the lattice energy of RbCl using the following data:

Question 54

In not more than three sentences, describe the key features of bonding in solid aluminum.

Question 55

Give a clear and concise definition of the term "electronegativity"; i.e., what does it measure?

Question 56

A hypothetical ionic substance will not form merely because it has a high lattice energy. Explain why, using energy-based arguments.

Question 57

The melting points of metals are only moderately high because

A) metallic bonding is weak.
B) metals have fewer bonding electrons than non-metals.
C) metals also have relatively low boiling points.
D) the melting process does not break the metallic bonds.
E) metals prefer to be bonded to non-metals.

Question 58

Which of the following compounds displays the greatest ionic character in its bonds?

A) NO₂
B) CO₂
C) H₂O
D) HF
E) NH₃

Question 59

Analysis of an unknown substance showed that it has a moderate melting point and is a good conductor of heat and electricity in the solid phase. Which of the following substances would have those characteristics?

A) NaCl
B) Si
C) CCl₄
D) I₂
E) Ga

Question 60

Describe, with appropriate explanations, the key factors which affect the magnitude of the lattice energy of an ionic substance.

Question 61

The electrostatic energy of two charged particles is inversely proportional to the square of the distance between them.

Question 62

The electrostatic energy of two charged particles is inversely proportional to the distance between them.

Question 63

The stronger the bonds in a fuel, the more energy it will yield.

Question 64

The more C O and O H bonds there are in a substance, the greater will be the amount of heat released when a fixed mass of the substance is burned.

Question 65

Electronegativities on Pauling's scale are calculated from ionization energies and electron affinities.

Question 66

Covalently bonded substances do not necessarily exist as separate molecules.

Question 67

Bond energy increases as bond order increases, for bonding between a given pair of atoms.

Question 68

No real bonds are 100% ionic in character.

Question 69

The lattice energy is the energy released when separated ions in the gas phase combine to form ionic molecules in the gas phase.

Question 70

A single covalent bond consists of a single delocalized electron pair.

Question 71

The lattice energy of large ions is greater in magnitude than that of small ions of the same charge.

Question 72

In covalent bond formation, the potential energy reaches a maximum when the internuclear distance is equal to the bond length.

Question 73

As a measure of the strength of metallic bonding, the boiling point of a metal is a better indicator than its melting point.