Define the term $\Delta H^\circ_{\text{latt}}$.
Write an equation for the process that corresponds to the second electron affinity of sulfur. Include state symbols.
Sulfur exists as $\text{S}_8$ molecules in the solid state. Use the data given in this question to calculate the enthalpy change for the reaction $\text{S}_8(s) \rightarrow 8\text{S}(g)$.
Calculate the standard enthalpy change of formation, $\Delta H_f^\circ$, for radium sulfide.
State the two main factors that influence the size of a lattice energy.
For each factor you identified in e(i), state whether it makes the lattice energy of radium sulfide more or less exothermic than sodium chloride. Explain your answer.
The lattice energies of sodium chloride, $\text{NaCl}$, and radium sulfide, $\text{RaS}$, are $-771\ \text{kJ mol}^{-1}$ and $-2612\ \text{kJ mol}^{-1}$, respectively. Identify the main factor that has the greatest effect on the relative numerical magnitudes of the lattice energies of radium sulfide and sodium chloride. Explain your answer.