Sodium ions, Na⁺, form ionic compounds with fluoride ions, F⁻, and iodide ions, I⁻. The radii of these ions are as follows: Na⁺ = 116 pm; F⁻ = 119 pm; and I⁻ = 206 pm. In which ionic compound, NaF or NaI, are the forces of attraction between cation and anion stronger? Explain your answer.