Here is the completely updated `question.php`. I added the missing `$breadcrumbs` array and defined `$category_name` and `$topic_name` right before the header is included. This ensures that `header.php` generates the correct Breadcrumb Schema, page title, and meta description for single question pages. Replace your entire `question.php` with this: ```php Ionic Bonding & Lattice Energy Questions
TestMaster MCQs

Ionic Bonding & Lattice Energy Questions

Home Chemistry Ionic Bonding & Lattice Energy
Q. An ionic bond is formed by:
Electrostatic attraction between oppositely charged ions
Overlap of atomic orbitals
Delocalization of electrons in a metal lattice
Sharing of electron pairs between atoms

Explanation:

Ionic bonds result from the electrostatic attraction between oppositely charged ions formed when one atom transfers electrons to another.

Q. Which of the following pairs is most likely to form an ionic compound?
Potassium and chlorine
Hydrogen and chlorine
Carbon and oxygen
Nitrogen and nitrogen

Explanation:

Ionic bonds form between metals with low ionization energy and nonmetals with high electron affinity. K (alkali metal) and Cl (halogen) form KCl, a classic ionic compound.

Q. Lattice energy is defined as:
The energy released when an electron is added to an atom
The energy required to melt an ionic solid
The energy required to remove an electron from an atom
The energy released when gaseous ions form one mole of an ionic solid

Explanation:

Lattice energy is the energy released when one mole of an ionic solid forms from its gaseous ions, or equivalently the energy needed to separate one mole of the solid into gaseous ions.

Q. Lattice energy increases with:
Higher ionic charges and smaller ionic radii
Lower ionic charges and larger ionic radii
Lower ionic charges only
Larger ionic radii only

Explanation:

According to Coulomb's law, lattice energy is proportional to the product of the ionic charges (q1·q2) divided by the interionic distance (r). Higher charges and smaller radii both increase lattice energy.

Q. Which compound has the highest lattice energy?
KCl
MgO
NaF
NaCl

Explanation:

MgO has Mg²⁺ and O²⁻ ions with high charges and small radii, giving it a much larger lattice energy than compounds with +1/−1 charges such as NaCl, KCl, or NaF.

Q. Which of the following ionic compounds would be expected to have the highest melting point?
MgO
NaCl
NaI
KBr

Explanation:

Higher lattice energy correlates with higher melting points. MgO (2+/2− charges, small radii) has the highest lattice energy among the given options, so it melts at the highest temperature.

Q. The Born-Haber cycle is used to determine:
The rate of an ionic reaction
The activation energy of a reaction
The lattice energy of an ionic compound
The pH of a solution

Explanation:

The Born-Haber cycle applies Hess's law to calculate the lattice energy of an ionic compound from measurable quantities: sublimation, ionization, dissociation, electron affinity, and formation enthalpy.

Q. Which of the following is a property characteristic of ionic compounds?
They conduct electricity in the solid state
They are typically gases at room temperature
They have low melting points
They conduct electricity in the molten or aqueous state

Explanation:

Ionic compounds conduct electricity when molten or dissolved (because ions are free to move), but not in the solid state (where ions are locked in the lattice).

Q. Ionic compounds typically dissolve in water because:
Water's high polarity stabilizes the ions, overcoming lattice energy
Water is a strong acid
Water reacts chemically with the ions
Water is non-polar

Explanation:

Water is a polar solvent with a high dielectric constant. Its partial charges stabilize both cations (via oxygen lone pairs) and anions (via hydrogen atoms), and the ion-dipole interactions overcome lattice energy.

Q. The energy required to remove an electron from a gaseous atom is called:
Bond dissociation energy
Lattice energy
Ionization energy
Electron affinity

Explanation:

Ionization energy is the minimum energy required to remove the most loosely bound electron from an isolated gaseous atom.

Q. The energy released when an electron is added to a gaseous atom is called:
Lattice energy
Electronegativity
Electron affinity
Ionization energy

Explanation:

Electron affinity is the energy change (usually negative/released) when an electron is added to a neutral gaseous atom.

Q. The Born equation predicts that hydration enthalpy is proportional to:
r/z (radius divided by charge)
z/r² (charge divided by radius squared)
z²/r (charge squared divided by radius)
z·r (charge times radius)

Explanation:

The Born equation gives ΔG_hydration ∝ -z²/r, where z is the ion charge and r its radius. Smaller, highly charged ions are more strongly hydrated.

Q. Which of the following ions has the smallest ionic radius?
Na⁺
O²⁻
Al³⁺
F⁻

Explanation:

Isoelectronic ions: N³⁻, O²⁻, F⁻, Na⁺, Mg²⁺, Al³⁺ all have 10 electrons. Higher positive charge pulls the electron cloud closer, so Al³⁺ has the smallest ionic radius.

Q. Which is the correct formula for the ionic compound formed from calcium and nitride ions?
Ca₃N₂
Ca₃N
CaN
Ca₂N₃

Explanation:

Ca forms Ca²⁺ and nitride is N³⁻. Charge balance requires 3 Ca²⁺ and 2 N³⁻ to give neutrality: Ca₃N₂.

Q. Which of the following statements about ionic solids is FALSE?
They are poor electrical conductors in the solid state
They are hard and brittle
They deform easily under mechanical stress
They have high melting points

Explanation:

Ionic solids are typically hard and brittle, but they shatter (not deform) under stress because the ions are rigidly ordered. The claim that they deform easily is false.

Q. Which factor most strongly affects the solubility of an ionic compound in water?
Crystal color
Nature of the cation only
Molecular mass only
Balance between lattice energy and hydration energy

Explanation:

Solubility depends on the balance between the lattice energy (favoring the solid) and the hydration energies of the ions (favoring dissolution). When hydration dominates, the salt dissolves.

Q. Which of the following compounds is LEAST likely to exist as an ionic solid?
MgO
KBr
CCl₄
NaCl

Explanation:

Ionic character depends on electronegativity difference. CCl₄ is covalent (small ΔEN, nonpolar solvent-like properties). The others are predominantly ionic (metal + nonmetal).

Q. The strength of an ionic bond is inversely related to:
The charges on the ions
The distance between the ions
The dielectric constant of the medium
The atomic masses of the ions

Explanation:

According to Coulomb's law (F ∝ q₁·q₂/r²), force is inversely related to the square of the distance between ions. Larger ions produce weaker ionic bonds.

Q. An ionic bond is most likely formed between elements with:
Identical electronegativities
The same ionization energies
A large electronegativity difference
Similar electronegativities

Explanation:

Large electronegativity differences (typically >1.7) favor electron transfer from a metal (low electronegativity) to a nonmetal (high electronegativity), producing ions.

Q. Which ionic compound is expected to be the most soluble in water?
SrSO₄
MgSO₄
BaSO₄
CaSO₄

Explanation:

Solubility of alkaline earth sulfates decreases down the group (BeSO₄ > MgSO₄ > CaSO₄ > BaSO₄) because lattice energy decreases more slowly than hydration energy. MgSO₄ is much more soluble than BaSO₄.

Q. The lattice enthalpy of an ionic solid can be estimated using:
The Kapustinskii or Born-Landé equation
The Nernst equation
The van der Waals equation
The Henderson-Hasselbalch equation

Explanation:

The Kapustinskii equation (like the Born-Landé equation) estimates lattice enthalpy from charges and ionic radii. The Born-Landé and Kapustinskii equations are standard textbook methods.

Q. In the Born-Haber cycle for NaCl, which step requires energy input?
Sublimation of Na only
Formation of NaCl lattice
Ionization of Na and dissociation of Cl₂
Electron affinity of Cl

Explanation:

Removing an electron from Na (ionization energy) and dissociating Cl₂ require energy. Sublimation of Na and ionization of Na are endothermic; Cl₂ bond breaking is endothermic; Cl electron affinity and lattice formation are exothermic.

Q. Which of the following has the greatest ionic character?
HI
HCl
HBr
KF

Explanation:

Ionic character correlates with electronegativity difference. Among these, KF has the largest ΔEN (K 0.82, F 3.98 → ΔEN ≈ 3.16), making it the most ionic.

Q. Fajans' rules predict that a covalent bond is more likely when:
Both ions are large and singly charged
The cation is large and the anion is small
The cation is small and highly charged and the anion is large and polarizable
Both ions have the same electronegativity

Explanation:

Fajans' rules: high cation charge, small cation size, and large anion size all favor polarization of the anion by the cation, giving more covalent character. LiI satisfies all three.

Q. Which of the following pairs of ions would form the strongest ionic bond?
Cs⁺ and I⁻
Na⁺ and Cl⁻
K⁺ and Br⁻
Al³⁺ and O²⁻

Explanation:

Lattice energy ∝ (q₁q₂)/r. Al³⁺ and O²⁻ have the highest charges (3+/2−) and relatively small radii, so Al₂O₃ has exceptionally strong ionic bonding.

Popular Topics

```