What does first electron affinity mean?
The first electron affinity of an atom is usually exothermic, but the second electron affinity is endothermic. Suggest why.
Describe the overall trend in first electron affinities for $\text{Cl}$, $\text{Br}$ and $\text{I}$. Explain your answer.
Calculate the first electron affinity for iodine. Use the relevant data from Table 3.1 in your working. Drawing a labelled energy cycle may help. Show all working.
Predict how $\Delta H^\circ_{\text{latt}}$ of $\text{CdI}_2(s)$ compares with $\Delta H^\circ_{\text{latt}}$ of $\text{ZnI}_2(s)$. Put a tick (✓) in the correct box in Table 3.2. Explain your answer.
Predict how $\Delta H^{\ominus}_{\text{latt}}$ of $\text{CdI}_2(s)$ compares with $\Delta H^{\ominus}_{\text{latt}}$ of $\text{ZnI}_2(s)$. Put a tick (✓) in the correct box in Table 3.2. Explain your answer.