Chapter 3 - Exercises - Page 150c: 60

See the explanation

Lattice energy depends mainly on two factors (from the Born–Landé equation): Charge of ions: higher charges → stronger attraction → more negative lattice energy. Size of ions: smaller ions → stronger attraction → more negative lattice energy. Lattice energy increases in magnitude (becomes more negative) with smaller ions and higher ionic charges. (a) LiF vs. CsF Both: M⁺F⁻ Li⁺ is much smaller than Cs⁺ → stronger attraction. Most negative: LiF (b) NaBr vs. NaI Both: Na⁺X⁻ Br⁻ smaller than I⁻ → stronger attraction. Most negative: NaBr (c) BaCl₂ vs. BaO Ba²⁺Cl⁻ vs. Ba²⁺O²⁻ Charges: Ba²⁺ + O²⁻ = 2 × 2 → higher than Ba²⁺ + Cl⁻ = 2 × 1 Both cations similar size; O²⁻ smaller than Cl⁻ anyway Most negative: BaO (d) Na₂SO₄ vs. CaSO₄ Na₂SO₄: 2 Na⁺ (1⁺ each) + SO₄²⁻ CaSO₄: Ca²⁺ + SO₄²⁻ Ca²⁺ + SO₄²⁻ has higher charges → stronger attraction Most negative: CaSO₄ (e) KF vs. K₂O KF: K⁺ + F⁻ → charges = 1 × 1 K₂O: 2 K⁺ + O²⁻ → effective interaction = 2 × 2 (stronger) Most negative: K₂O (f) Li₂O vs. Na₂S Li₂O: Li⁺ + O²⁻ Na₂S: Na⁺ + S²⁻ Compare cation sizes: Li⁺ smaller than Na⁺ → stronger attraction Compare anion sizes: O²⁻ smaller than S²⁻ → stronger attraction Most negative: Li₂O