These are physical properties of an element (a) Sublimation enthalpy (b) Ionisation enthalpy (c) Hyd — p Block Elements Chemistry Question

💡 Solution & Explanation

**Step 1: Recall the Born-Landé equation for reduction potential** The reduction potential (E°) of an element depends on the thermodynamic cycle involving ionization and hydration of ions. The key relationship is: E° ∝ (Ionization Enthalpy + Hydration Enthalpy) / (other factors) **Step 2: Analyze Ionization Enthalpy** Ionization enthalpy (IE) is required to remove electrons from the neutral atom. Higher IE means the element is harder to oxidize, affecting reduction potential directly. ✓ Affects E° **Step 3: Analyze Hydration Enthalpy** Hydration enthalpy (ΔH_hyd) is released when gaseous ions are hydrated in solution. This energy release stabilizes the ion, making reduction more favorable. ✓ Affects E° **Step 4: Analyze Sublimation Enthalpy** Sublimation enthalpy converts solid metal to gaseous atoms. This is part of the thermodynamic cycle for reduction potential. ✓ Affects E° **Step 5: Analyze Electron Gain Enthalpy** Electron gain enthalpy applies to non-metals gaining electrons (reduction). For metal reduction potentials (M → M^n+), this doesn't apply. ✗ Does not affect E° **Step 6: Count the properties** Properties affecting reduction potential: - Sublimation enthalpy (a) ✓ - Ionization enthalpy (b) ✓ - Hydration enthalpy (c) ✓ - Electron gain enthalpy (d) ✗ Therefore, the answer is 3.00.