Answer to Question #340328 in General Chemistry for Kreshna

Question

Is the ionization energy of phosphorus greater than the ionization energy of sulfur? If so, is the electron affinity of phosphorus also greater than the electron affinity of sulfur? Thank you.

Answer 1

The first ionisation energy of phosphorus is less than that of sulfur. (1) More energy is required to overcome the attraction between the paired 3p electrons in sulfur. (2) 3p electrons of sulfur are further away from the nucleus compared to that of phosphorus.

Since the 3p electrons in sulfur (that sulfur would lose) are paired, sulfur has more electron repulsion in those orbitals than phosphorus does, so it takes less energy input to remove an electron from sulfur.