Consider an ionic compound, mxmx , composed of generic metal mm and generic, gaseous halogen xx . the enthalpy of formation of mxmx is δh∘f=−421δhf∘=−421 kj/mol. the enthalpy of sublimation of mm is δhsub=155δhsub=155 kj/mol. the ionization energy of mm is ie=401ie=401 kj/mol. the electron affinity of xx is δhea=−321δhea=−321 kj/mol. (refer to the hint). the bond energy of x2x2 is be=239be=239 kj/mol. determine the lattice energy of mxmx .