a. Suggest why the 2nd and 3rd electron affinities are always endothermic.

b. The 1st electron affinity of sulfur is –200 kJ mol^–1. The second electron affinity of sulfur is +640 kJ mol^–1. Calculate a value for the enthalpy change S(g) + 2e^–→ S2^–(g)

c. Write equations representing:

i. The 1st electron affinity of iodine

ii. The 2nd electron affinity of sulfur