Write equations corresponding to the following energy terms.
a. the fourth ionization energy of $\mathrm{Se}$
b. the electron affinity of $S^{-}$
c. the electron affinity of $\mathrm{Fe}^{3+}$
d. the ionization energy of $\mathrm{Mg}$
e. the work function of Mg (see Exercise 27 )
