Question 1

What is the formal charge of boron in BH3?

Accepted Answer

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

Question 2

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

Accepted Answer

A) True 
 B)False  True

Question 3

Explain the relationship between lattice energies and physical properties.

Accepted Answer

The melting point is the temperature at which the individual ions have enough kinetic energy to overcome the attractive forces that hold them in place. At the melting point, the ions can move freely, and the substance becomes a liquid. Thus, melting points vary with lattice energies for ionic substances that have similar structures.
The Hardness of ionic materials, that is, their resistance to scratching or abrasion, is also related to their lattice energies. Hardness is directly related to how tightly the ions are held together electrostatically, which, is also reflected in the lattice energy. In addition to determining melting point and Hardness, lattice energies affect the solubilities of ionic substances in water. In general, the higher the lattice energy, the less soluble a compound is in water.

Question 4

Which of the following compounds has the highest lattice energy?

Accepted Answer

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

Question 5

Ions cannot be infinitely close together.

Accepted Answer

A) True 
 B)False

Question 6

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

Accepted Answer

The answer of _____ molecules are those which have less...

Question 7

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

Accepted Answer

A) True 
 B)False

Question 8

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

Accepted Answer

A) True 
 B)False

Question 9

Electron-deficient molecules are Lewis bases.

Accepted Answer

A) True 
 B)False

Question 10

Triple bonds between like atoms are longer than double bonds.

Accepted Answer

A) True 
 B)False

Question 11

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

Accepted Answer

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. 
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 12

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

Accepted Answer

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)  $Q r$ 
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 13

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.

Accepted Answer

internucle

Question 14

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

Accepted Answer

total ener

Question 15

Explain the three features of chemical bonding.

Accepted Answer

All models of chemical bonding have thre

Question 16

Which of the following is true of a formal charge?

Accepted Answer

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. 
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 17

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

Accepted Answer

A) True 
 B)False

Question 18

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

Accepted Answer

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

Question 19

Explain the significance of the energy of the electrostatic attraction.

Accepted Answer

The energy of the electrostatic attracti

Question 20

Which of the following is true of bond polarity?

Accepted Answer

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. 
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.

Exam 8: Ionic Versus Covalent Bonding

What is the formal charge of boron in BH3?

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

Explain the relationship between lattice energies and physical properties.

Which of the following compounds has the highest lattice energy?

Ions cannot be infinitely close together.

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

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

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

Electron-deficient molecules are Lewis bases.

Triple bonds between like atoms are longer than double bonds.

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

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

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.

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

Explain the three features of chemical bonding.

Which of the following is true of a formal charge?

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

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

Explain the significance of the energy of the electrostatic attraction.

Which of the following is true of bond polarity?

Introduction to Chemistry

Molecules, Ions, and Chemical Formulas

Chemical Reactions

Reactions in Aqueous Solution

Energy Changes in Chemical Reactions

The Structure of Atoms

The Periodic Table and Periodic Trends

Molecular Geometry and Covalent Bonding Models

Gases

Liquids

Solids

Solutions

Chemical Kinetics

Chemical Equilibrium

Aqueous Acidbase Equilibriums

Solubility and Complexation Equilibriums

Chemical Thermodynamics

Electrochemistry

Nuclear Chemistry

Periodic Trends and the S-Block Elements

The P-Block Elements

The D-Block Elements

Organic Compounds

Filters

What is the formal charge of boron in BH₃?

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

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