Question

Determine the type of bond in each pair of atoms. Which is the most polar bond? Least polar? Support your answers by calculating the electronegativity difference in each pair.

Cl - F, O - S, P - N, Na - Cl

Answer 1

Cl – F – covalent polar, ΔEN = 3.98 – 3.16 = 0.82 > 0.4   

O – S – covalent polar, ΔEN = 3.44 – 2.58 = 0.86 > 0.4

P – N – covalent polar, ΔEN = 3.04 – 2.19 = 0.85 > 0.4  

Na – Cl – ionic bond between cation Na⁺ and anion Cl^-, ΔEN = 3.16 – 0.93 = 2.23 >> 0.4

The most polar is Na – Cl, the least polar is Cl – F.