Consider the gas-phase transfer of an electron from a sodium atom to a chlorine atom

Chapter 7, Problem 7.108

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Consider the gas-phase transfer of an electron from a sodium atom to a chlorine atom: Na{g) + Cl{g) ----> Na+{g) + Cl-{g) (a) Write this reaction as the sum of two reactions, one that relates to an ionization energy and one that relates to an electron affinity. (b) Use the result from part (a), data in this chapter, and Hess's law to calculate the enthalpy of the above reaction. Is the reaction exothermic or endothermic? (c) The reaction between sodium metal and chlorine gas is highly exothermic and produces NaCl(s), whose structure was discussed in Section 2.7. Comment on this observation relative to the calculated enthalpy for the aforementioned gas-phase reaction.