What does the term electron affinity mean?
Write the equation for the process that represents the second ionisation energy of calcium. Include state symbols.
Oxygen is present as $\text{O}_2$ molecules. Use the information provided to calculate the bond energy of the $\text{O=O}$ bond. Show your working.
Suggest why oxygen has a negative first electron affinity.
Suggest why the second electron affinity of oxygen is positive.
Calculate the enthalpy of formation for calcium oxide, $\text{CaO(s)}$.
The lattice energy of lithium fluoride, $\text{LiF(s)}$, is $-1022\,\text{kJ mol}^{-1}$. Identify the factor that makes the lattice energy of calcium oxide more exothermic than that of lithium fluoride. Explain why this factor leads to the difference in lattice energies.