CHEM 111 Smart Book 9
The percent ionic character is a calculation that quantitatively describes a bond as polar, nonpolar, or ionic. It is the ratio of the observed versus calculated _______ of the bond.
dipole moment
Coulomb's law states that the force (F) between two charges is _____ proportional to the product of their charges and _____ proportional to the distance between them.
directly, inversely
Elements with low ionization energies tend to form _____. Elements with high positive electron _____ tend to form _____.
cations; affinities; anions
When we study bonding between two atoms, we are concerned primarily with the ______ electrons of the atoms.
valence
Which of the following Lewis structures is the most plausible for hydrogen cyanide (formal charges may have been deliberately omitted)?
A
Using the table of electronegativities provided arrange the following bonds in order of increasing ionic character. Place the least polar bond at the top of the list. Instructions
- Pd-H - C-H - N-O - F-Cl
Which of the following statements correctly defines an ionic bond?
An ionic bond is the electrostatic force that holds oppositely charged ions together in an ionic compound.
Which of the following are plausible resonance structures for nitrite anion (NO2-)?
- B - C
- KF - MgI2 - CaF2
- F ∝ -0.14 - F ∝ -0.23 - F ∝ -0.37
Determine the magnitude of the partial and positive and negative charges in hydrogen iodide (HI) given the following data: HI bond length = 1.61 angstroms; HI dipole moment = 0.44 D; 1 D = 3.336 x 10-30 C⋅m; 1e- = 1.6022 x 10-19 C
+5.8 x 10-2 on H and -5.8 x 10-2 on I
Consider the equations shown. Use the Born-Haber cycle to estimate the lattice energy of lithium chloride (LiCl).
+862 kJ/mol
When the elements Mg and Cl form an ionic bond, Mg loses ______ electron(s) from the 3s orbital to form the Mg2+ cation. Cl gains ______ electron(s) in the 3p orbital to form the Cl- anion. Since the total number of electrons lost always equals the total number of electrons gained, the compound formed will contain ______ Mg2+ ion(s) for every ______ Cl- ion(s). Fill in the blanks with the appropriate numbers.
- 2 - 1 - 1 - 2
- A - B - C - D
- 2- - 0 - 1- - 1+ - 2+
- A - B - C - D
- 6 lone pairs - 2 lone pairs - 0 lone pair - 1 lone pairs
- A - B - C - D
- 6A - 1A - 7A - 4A
Certain molecules are electron deficient, having fewer than _____ electrons around the central atom. Elements that commonly form electron deficient compounds are beryllium and ______. (One word answer.)
- 8 - boron
Which of the following are correct Lewis dot symbols for the ions shown? Select all that apply.
- A - B - C
Which of the following are correct Lewis dot symbols for nitrogen? Select all that apply.
- A - C
Which of the following species are free radicals? Select all that apply
- A - C
Place the following bonds in order of increasing bond length, with the shortest bond at the top of the list.
- A - C - B
Which of the following are possible resonance structures for hydrogen cyanide (HCN)?
- A - D
Which of the following statements correctly describe a coordinate covalent bond? Select all that apply.
- A coordinate covalent bond is also known as a dative bond. - A coordinate covalent bond is a covalent bond formed between two atoms where one of the atoms donates both of the bonding electrons.
Which of the following statements correctly describe a polar covalent bond? Select all that apply.
- A covalent bond between atoms whose electronegativities differ is polar. - In a polar covalent bond the electron density is highest near the more electronegative atom.
Which of the following statements correctly relate bond type to electronegativity? Select all that apply.
- A covalent bond forms between two atoms that have an electronegativity difference of 2.0 or less. - An ionic bond forms between two atoms that have an electronegativity difference of 2.0 or more. - The hydrogen-chlorine bond is covalent.
Which of the following statements correctly relate percent ionic character and electronegativity differences to the nature of a particular bond? Select all that apply.
- A purely covalent bond has 0% ionic character. - The bond in NaF (electronegativity difference between the two atoms is 3.1) has a large percentage of ionic character. - A chlorine-chlorine bond has 100% covalent character.
Select all statements that correctly connect the thermochemical nature of a reaction with the magnitude of the bond enthalpies of products and reactants.
- A reaction is exothermic if the total enthalpy required to break bonds in the reactants is less than the total enthalpy released by bond formation. - For polyatomic molecules the equation for enthalpy of reaction will yield approximate results, since the bond enthalpies used are averages.
Which of the following options correctly describe the guidelines used to select the most plausible Lewis structure for a given covalent species? Select all that apply.
- A structure is preferred in which a negative charge resides on a more electronegative atom. - A structure with smaller formal charges on individual atoms is preferred.
Which of the following options correctly describe the guidelines used to select the most plausible Lewis structure for a given covalent species? Select all that apply.
- A structure with smaller formal charges on individual atoms is preferred. - A structure is preferred in which a negative charge resides on a more electronegative atom.
Which of the following statements correctly describe resonance structures? Select all that apply.
- An individual resonance structure does not accurately represent the structure of the species. - Resonance structures differ only in the arrangement of electrons.
Select all statements that correctly relate the type of bond formed between two elements and their relative electronegativities.
- Atoms of comparable electronegativities tend to form polar covalent bonds. - Atoms with widely differing electronegativities tend to form ionic bonds. - A pure covalent bond is formed between atoms of the same element that have the same electronegativity.
In each of the following structures one of the atoms is labeled with an arrow. Select all structures in which the labeled atom obeys the octet rule (possesses eight electrons).
- B - D - E
Which of the following elements typically form covalent compounds in which they have less than a full octet of electrons in their valence shell? Select all that apply.
- Boron - Beryllium
Using the electronegativity values shown, select all bonds that are polar covalent bonds.
- C-Cl - N-B
Using the table of electronegativity values provided, select all the bonds from the following list that are polar.
- C-N - H-O - B-Cl
- 24 - 32 - 18 - 14 - 8
- CO3^2- - BF4^- - NO2^- - HO2^- - NH4^-
Arrange the following ionic compounds in order of increasing lattice energy (increasing strength of the ionic bond) based on general trends in lattice energy. Start with the compound that has the lowest lattice energy at the top of the list.
- CaBr2 - MgCl2 - Li2O
- Na - F
- Cation - Anion
Bond enthalpies of particular bonds (e.g., O-H) vary from compound to compound because of changes in the _______ environment of the bond under investigation. We can measure the enthalpy of a particular bond in a number of compounds and obtain the _______ bond enthalpy by dividing the sum of the bond enthalpies by the total number of compounds.
- Chemical - Average
Which of the following Lewis symbols correctly represent that element? Select all that apply.
- Cl - N - C
Which of the following elements may have an expanded valence shell? Select all that apply.
- Cl - S - Xe
Which of the following statements correctly describe how to calculate the total number of valence electrons for a polyatomic anion or cation? Select all that apply.
- Count the total number of valence electrons for all atoms in the structure. - For each positive charge in the ion subtract 1 from the total number of valence electrons of the atoms. - For each negative charge in the ion add 1 to the total number of valence electrons of the atoms.
Select all statements that correctly describe how dots are placed around a Lewis dot symbol.
- Dots are placed above and below as well as to the left and the right of the element symbol. - The exact order in which dots are placed around the element symbol is not important. - Dots are not paired until absolutely necessary when drawing a Lewis dot symbol.
The following are basic steps that are used for drawing Lewis structures. List these steps in the correct order for drawing a Lewis structure (the first step should be placed at the top and the last step at the bottom of the list). Instructions
- Draw the skeletal structure.... - count the total number.... - for each bond.... - use the remaining..... - if any electrons.... - if the central atom...
Which of the following statements describe the Born-Haber cycle correctly? Select all that apply.
- Electron affinity is a component of the Born-Haber cycle. - The Born-Haber cycle is an application of Hess's law.
- Pure covalent bond (nonpolar) - Polar covalent bond - Ionic bond
- Electronegativites differ by <0.5. - Electronegativites differ by a range of 0.5-2.0. - Electronegativites differ by >2.0.
Which of the following options correctly describe electronegativity? Select all that apply.
- Electronegativity is a relative concept. - Electronegativity measures the ability of an atom in a compound to attract electrons to itself.
Which of the following statements correctly describe electronegativity and electron affinity? Select all that apply.
- Electronegativity is the ability of an atom to attract toward itself the electrons in a chemical bond. - Atoms with a high electronegativity generally have high values of electron affinity.
Which of the following statements correctly describe a Lewis dot symbol? Select all that apply.
- Elements in the same group have similar electron configurations and hence similar Lewis dot symbols. - Each dot in a Lewis dot symbol represents a valence electron.
Which of the following statements correctly describe the steps followed when drawing a Lewis structure? Select all that apply.
- For polyatomic anions, add the number of negative charges to the total number of valence electrons. - Valence electrons must be shown as lone pairs if they are not involved in bonding. - In general, the least electronegative atom should occupy the central position in the Lewis structure.
Which of the following statements correctly describe formal charge? Select all that apply.
- Formal charges can be used to select the most plausible Lewis structures when more than one possibility exists for a compound. - The formal charge of an atom is the charge it would have if all bonding electrons were shared equally.
Which of the following Lewis symbols correctly represent the element shown? Select all that apply.
- H - S - P
Why does an ionic solid not conduct electricity in the solid state but is a good conductor when melted or dissolved in water? Select all that apply.
- In the liquid or dissolved state, the ions are free to move and can carry an electric current. - In the solid state, the ions are held in specific positions and are not free to move.
Which of the following statements correctly describe ionic bonding? Select all that apply.
- Ionic bonding involves the transfer of electrons from the metal to the nonmetal. - An ionic bond is the electrostatic attraction between two oppositely charged ions.
- B - A
- Less stable - More stable
Which of the following statements correctly describe a Lewis structure? Select all that apply.
- Lone pairs are shown as pairs of dots on individual atoms. - Bonding electrons are shown as dashes or pairs of dots between two atoms.
Select all statements that correctly describe lone pairs of electrons.
- Lone pairs of electrons are not involved in covalent bonding. - Lone pairs of electrons are valence electrons.
Which of the following Lewis dot symbols are correct? Select all that apply.
- Mg2+ - Na+
Arrange the following ionic compounds in order of decreasing lattice energy (decreasing strength of the ionic bond) based on general periodic trends. Start by placing the compound with the highest lattice energy at the top of the list.
- MgO - Na2O - KBr
Which of the following statements correctly describe trends in lattice energy? Select all that apply.
- NaCl is expected to have a higher lattice energy than NaBr. - The lattice energy of an ionic compound tends to decrease as ionic size increases.
Consider the molecule shown. Select all statements that correctly describe this structure.
- Oxygen has 8 valence electrons. - Fluorine has 3 lone pairs of electrons. - Oxygen has 2 lone pairs of electrons.
Select all statements that correctly define the term percent ionic character.
- Percent ionic character is defined as the ratio of observed μ to calculated μ for complete charge separation, multiplied by 100. - Percent ionic character is a quantitative way to describe the nature of a bond.
The formation of an ionic compound involves a number of different processes. In the formation of sodium chloride, represented by the equation given below, which steps absorb energy? Select all that apply. 2Na (s) + Cl2 (g) → 2NaCl (s)
- Removal of an electron from Na - Dissociation of Cl2 to form 2Cl - Conversion of Na (s) → Na (g)
Which of the following statements correctly describe resonance structures? Select all that apply.
- Resonance structures differ only in the arrangement of electrons. - An individual resonance structure does not accurately represent the structure of the species.
Of the structures shown, structure B is the most plausible Lewis structure for isocyanate ion (NCO-). Select the statements that would guide you to this conclusion.
- Structure A is less stable than structure B as the negative formal charge is on a less electronegative atom in A. - Structure C has a -2 formal charge on N. Structures bearing large formal charges are less stable than those with small formal charges. - Structure A is less stable than structure B as the negative formal charge is on a more electronegative atom in B.
Select the statements that correctly describe how the Born-Haber cycle may be used to determine the lattice energy.
- The Born-Haber cycle defines the steps that precede the formation of an ionic solid. - Each step in the Born-Haber cycle relates to energy changes for a mole of atoms/ions. - The lattice energy has the same value (but opposite sign) as the enthalpy of formation of the ionic solid from a mole of gaseous ions.
Which of the following statements correctly describe how formal charge is assigned to an atom in a Lewis structure? Select all that apply.
- The atom is considered to "own" half the bonding electrons. - The number of bonding electrons equals twice the number of bonds to the atom. - Formal charge = (valence e-) - (nonbonding e- + 1/2bonding e-)
Which of the following factors affect the magnitude of the lattice energy for an ionic compound? Select all that apply.
- The charges of the ions - The size of the ions
Which of the following statements correctly describe the general characteristics of a covalent bond? Select all that apply.
- The covalent bond involves the attraction between the nucleus of each atom and the shared electron pair. - A covalent bond involves the sharing of electrons between two atoms.
Select all statements that correctly define dipole moment (μ).
- The dipole moment is calculated as the product of the charge (Q) and the distance (r) between the charges. - A quantitative measure of the polarity of a bond is its dipole moment.
Which of the following statements correctly describe how to indicate the shift of electron density in a polar bond?
- The head of the arrow is placed above the more electronegative atom. - A dipole arrow is placed above the bond under consideration.
Which of the following statements correctly describes the term resonance?
- The properties of a molecule are best explained by the consideration of all possible resonance structures. - The ↔ symbol indicates that the structures shown are in resonance. - Resonance is a device used to address limitations in simple bonding models.
- Electronegativity - Electron affinity
- The relative ability of a bonded atom to draw electrons to itself. - The measured ability of an isolated atom to attract additional electrons.
Consider the formation of an ionic bond between the elements potassium (K) and chlorine (Cl). Which of the following statements describe this process correctly? Select all that apply.
- The total number of electrons lost equals the total number of electrons gained. - Both the K+ and Cl- ions have full outer shells containing 8 electrons. - K loses one electron from its 4s orbital to form a K+ cation.
- single bond - double bond - triple bond - multiple bond
- Two atoms share one pair of electrons. - Two atoms share two pairs of electrons. - Two atoms share three pairs of electrons. - Two atoms share two or three pairs of electrons.
Which of the following statements correctly describe a covalent bond? Select all that apply.
- Two electrons are shared between two atoms. - The shared pair of electrons is often represented by a single line.
- Ionic bond - Pure covalent bond - Polar covalent bond
- Two elements with widely differing electronegativities - Two identical elements - Two elements with comparable electronegativites
Which of the following statements correctly describe the different types of covalent bonds? Select all that apply.
- When atoms share three pairs of electrons the covalent bond between them is called a triple bond. - A multiple bond involves the sharing of two or more electron pairs between two atoms. - When atoms share two pairs of electrons the covalent bond between them is called a double bond.
Select all statements that correctly describe free radicals.
- When two free radicals collide the unpaired electrons tend to pair together and form a covalent bond. - Many free radicals are highly reactive.
Most covalently bonded substances consist of individual separate molecules. Each individual molecule is held together by means of strong ______ bonds between the atoms. In addition, there are weak forces of attraction between the individual molecules, called ______ forces.
- covalent - intermolecular
The bond formed between two nonmetals, which are usually very similar in their tendency to lose or gain electrons, is the ______ bond. This bond involves the ______ of one or more electron pairs between the two atoms.
- covalent - sharing
Lewis structures are used to represent covalent compounds. Shared electron pairs are shown either as dashes or as pairs of _____, and only the _______ electrons of atoms are shown.
- dots - valence
A Lewis dot symbol consists of the symbol of the ______, surrounded by dots representing the outer (valence) _____ in one atom of the element.
- element - electrons
Some elements do not obey the octet rule because they have more than eight valence electrons, i.e., they have an _____ valence shell. This is only possible for elements that have available ______ orbitals, i.e., elements from period ______ of the periodic table onward.
- expanded - d - 3
Molecules with an odd number of electrons are sometimes referred to as ______ _______.
- free - radicals
Lattice energy is defined as the energy required to completely separate one mole of a solid ______ compound into ______ ions
- ionic - gaseous
Most covalent substances do not conduct electricity, even when melted or in solution. An electric current is carried by the movement of either electrons or _______. In covalent substances the electrons are localized either as ______ pairs or lone pairs, and no ions are present.
- ions - bonded
Bond _____ is defined as the distance between the nuclei of two ______ bonded atoms in a molecule.
- length - covalently
- C-C bond - C-F bond - Na-F bond
- nonpolar covalent bond - polar covalent bond - ionic bond
For the main group elements, the number of dots in the Lewis dot structure is the same as the group _______. Transition metals are typically not represented by Lewis dot symbols as they have _____ filled inner shells.
- number - incompletely
A Lewis structure will usually require one or more multiple bonds if there is an atom present that does not have a full ______ after all available electrons have already been placed. The multiple bond is formed by exchanging one ______ electron pair for each additional bond.
- octet - lone
A covalent bond in which the electrons are shared unequally is called a(n) _____ covalent bond. The atoms of the bond have partial negative and positive ______ due to unequal electron distribution.
- polar - poles
A covalent bond is a bond in which two or more electrons are ______ between two atoms. The covalent bond is often represented by a pair of dots or a ______
- shared - line
An ionic solid does not conduct electricity in the _______ state because the ions are held together by strong attractive forces and cannot move from their positions in the crystal structure. If the solid melts or dissolves in water, the ions are free to move and carry a(n) ______ current.
- solid - electric
Some covalently bonded species do not obey the octet rule because they have an odd number of electrons. A species containing one or more ______ electrons is called a free radical. Many free radicals are highly reactive and tend to form a(n) _____ bond with an unpaired electron on another molecule.
- unpaired - covalent
Lewis dot structures are used to keep track of the total number of ______ electrons in a chemical reaction.
- valence
The formal charge assigned to an atom is calculated by subtracting the number of electrons the atom "owns" from its total number of ______ electrons. The number of electrons "owned" by a specific atom is defined as being the sum of the _____ valence electrons and half the ______ valence electrons.
- valence - unshared - shared
Consider the reaction shown, and select all the statements that correctly apply to the calculation of ΔHo for this reaction using the bond energies provided.
- ΔH for this reaction is equal to -168 kJ/mol. - In this reaction two C - Cl bonds are formed.
Which of the following statements correctly describe the procedure used to calculate ΔHo for a reaction using bond enthalpies? Select all that apply.
- ΔHo for the reaction is given by ΣBE(reactants) -ΣBE(products) - The sum ΔHbonds broken is given a positive value.
Determine the magnitude of the partial and positive and negative charges in hydrogen chloride (HCl) given the following data: HCl bond length = 1.27 angstroms; HCl dipole moment = 1.08 D; 1 D = 3.336 x 10-30 C⋅m; 1e- = 1.6022 x 10-19 C
-0.178 on Cl and +0.178 on H
The Lewis structure for the cyanide ion is shown. The formal charge on the C atom is equal to _____ and the formal charge on the N atom is equal to _____.
-1; 0
Use the bond enthalpies given to calculate the enthalpy of the reaction: 2H2(g) + O2(g) → 2H2O(g) H - H = 436.4 kJ/mol; H - O = 460 kJ/mol; O = O = 498.7 kJ/mol
-469 kJ/mol
Calculate the percent ionic character in the H-Br bond using data supplied in the table shown.
12% ionic character
Calculate the percent ionic character in the H-Cl bond using data supplied in the table shown.
17.7% ionic character
The octet rule states that an atom other than hydrogen tends to form bonds until it is surrounded by ______ valence electrons
8
Consider the equations shown. Use the Born-Haber cycle to determine the lattice energy of sodium fluoride (NaF).
925 kJ/mol
Select the correct Lewis structure for the molecule sulfur tetrafluoride (SF4).
A
Which of the following Lewis structures correctly represents the structure of formaldehyde (CH2O)?
A
The table shown gives the ionic radii of a set of ions. Using these data and Coulomb's law, calculate the attractive forces (F) between the ions in AlBr3 and LiF, and thus determine which compound has the higher lattice energy.
AlBr3 has the higher lattice energy. F ∝ -0.48 for AlBr3 and F ∝ -0.23 for LiF.
Which of the following Lewis structures correctly represents the structure of boron trifluoride (BF3)?
B
The _____ imagines the formation of an ionic compounds as occurring in a series of well-defined steps, each with its own change in enthalpy. _____ is used to combine the enthalpies of the steps in a way that gives the overall lattice energy.
Born-Haber cycle; Hess's law
Use formal charges to determine which of the two resonance structures is most important.
Bottom
Select the correct Lewis structure for the molecule xenon difluoride (XeF2).
C
Which statement best explains the factors that affect ionic bond strength in terms of electrostatic interactions?
Electrostatic attractions increase as the magnitude of the oppositely charged ions increases and their separation decreases.
When are multiple bonds needed in a Lewis structure?
If one or more atoms does not have an octet but all electrons have already been placed
Which of the following options correctly defines intermolecular forces?
Intermolecular forces are the weak forces of attraction found between the individual molecules of a covalent substance.
Which of the following options correctly defines resonance structures?
Lewis structures for the same species that differ in the placement of electrons
Which of the following statements best explains why most covalent substances do not conduct electricity, even when melted or in solution?
No ions are present to carry the charge.
Select the correct statement to explain why bond enthalpies are typically averaged values.
The average bond enthalpy is based on the same bond in different chemical environments.
Many covalent compounds are gases, liquids, or low-melting solids at room temperature. Which option correctly accounts for this behavior?
The intermolecular forces between the molecules typically require little energy to break.
Dipole moments are usually expressed in _____ units (D).
debye
Select the statement that correctly summarizes the steps to calculate ΔHo of a reaction using bond enthalpies.
The sum of the bonds formed (exothermic) in the reaction is subtracted from the sum of the bonds broken (endothermic).
Calculate the formal charges on each of the nitrogen atoms in the N3- ion shown. The overall charge of the ion has been omitted in the structure.
a = -1; b = +1; c = -1
The formation of an ionic compound involves the transfer of electrons. The removal of one or more electrons from a metal is a process that _____ energy, whereas the addition of one or more electrons to a nonmetal _____ energy.
absorbs; releases
Resonance structures are Lewis structures that have the same relative placement of _____ but a different arrangement of _____.
atoms; electrons
The distance between the nuclei of two covalently bonded atoms is the _____.
bond length
Knowing the _____ enthalpies and hence the _____ of reactant and product molecules allows us to determine the approximate enthalpy change of a given reaction.
bond, stability
Select the correct term for a bond in which one atom donates both electrons to the shared pair.
coordinate covalent bond
Anions that are isoelectronic with noble gases should have _____ dots around the element symbol. Square brackets should be placed around the symbol together with the _____ charge outside the brackets.
eight; negative
For two Lewis structure forms with the same formal charges, the structure that has the negative formal charge on the more ______ atom will be preferred.
electronegative
The ability of an atom in a compound to draw electrons to itself is called its _____. Electronegativity _____ from left to right across a period in the periodic table. Within a group, electronegativity _____ with increasing atomic number.
electronegativity, increases, decreases
The formal charge of an atom in a Lewis structure is the charge the atom would have if all bonding electrons were shared _______ between the atoms. The formal charge does not necessarily reflect an actual charge on the atom.
equally
The formation of ionic bonds is highly _____
exothermic
True or false: Resonance structures are different possible structures for the same species that interconvert rapidly.
false
The percent ionic character describes the nature of a bond by comparing observed dipole moment and the calculated one, which assumes the charges on the atoms are _____.
full
The formation of an ionic compound from the appropriate elements is _____.
highly exothermic
The lattice energy of an ionic solid is a measure of the attraction between the oppositely charged ions. As ionic charge increases, the attraction between the ions _____ and so does lattice energy. As the size of the ions increases, the attraction between the ions _____ and so does lattice energy. Lattice energy therefore _____ down a group of the periodic table and _____ across a period.
increases, decreases, decreases, increases
Covalent compounds typically have low melting and boiling point temperatures because of the strength of their _____.
intermolecular forces
The electrostatic force that holds oppositely charged ions together is called a(n) _____ bond.
ionic
Ionic compounds typically have high melting and boiling point temperatures because of the strength of their _____.
ionic bonds
The bond typically observed when a metal bonds to a nonmetal is the _____ bond. The metal atom _____ one or more valence electrons while the nonmetal _____ electrons.
ionic; loses; gains
The Born-Haber cycle relates the _____ energies of ionic compounds to ionization energies and electron affinities.
lattice
A quantitative measure of the stability of an ionic compound is its ______.
lattice energy
Pairs of valence electrons that are not involved in covalent bonding are known as _____ pairs
lone
Bond enthalpy is the enthalpy change required to break a particular bond in one ______ of gaseous molecules.
mole
Lewis dot structures of cations that are isoelectronic with noble gases should have _____ dots around the element symbol. Square brackets are _____ around the element symbol.
no; not placed
The term ______ means that at least two Lewis structures can be used to represent a particular covalent species. (Use only one word for your answer.)
resonance
For a given pair of atoms, a triple bond is _____ than a double bond.
shorter
Melting an ionic solid involves freeing the ions from their positions in the ionic crystal and separating them. Since the ions are held together by _____ electrostatic attractions the amount of energy required is _____ and ionic solids therefore have relatively _____ melting points.
strong, large, high
Bond enthalpy is defined as ______.
the enthalpy change required to break a particular bond in one mole of gaseous molecules
According to Coulomb's law the force (F) between two charges is directly proportional to _____.
the product of their charges
The charge separation between two elements that have a polar covalent bond between them may be indicated by placing a _____ on the more electronegative element and a _____ on the less electronegative element.
δ-; δ+
