Given the following data, calculate the second electron affinity of sulfur. Is the S^2– more stable as a free ion or in CaS?

• A. EA₂ = –365.3 kJ/mol
  S^2– is more stable as a free ion.
• B. EA₂ = –134.2 kJ/mol
  S^2– is more stable in CaS.
• C. EA₂ = 570.8 kJ/mol
  S^2– is more stable in CaS.
• D. EA₂ = 729.1 kJ/mol
  S^2– is more stable as a free ion.

Answer: (C)