Chemical Forums

Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: yourright on January 24, 2008, 08:15:31 PM

Title: Secret of Electron Affinity?
Post by: yourright on January 24, 2008, 08:15:31 PM

So we had this test question and it was a lattice energy question.  So they gave us the lattice energy, first ionization energy of unknown x, second ionization energy of unknown x, third ionization energy of unknown x, bond energy of unknown y, and electron affinity of of unknown y.  The question asked what was the total energy to form compound X₂y₃.  The process resulted in getting x⁺³ (g) + y^-2 (g).
Since the unknown y needed to become a -2 ion, I believed that you had to do the electron affinity twice, but my teacher said you only needed it once.  Will they always give you the total energies of the electron affinities?