Calcium has atomic number $20$. Complete the electronic structures for a calcium atom, $1s^22s^22p^6\,\ldots\ldots\ldots\ldots$, and for a calcium ion in the $+2$ oxidation state, $1s^22s^22p^6\,\ldots\ldots\ldots\ldots$.
Calcium nitrate, $\text{Ca(NO}_3)_2$, is used in fertilisers and can be made by an acid-base reaction. Write an equation showing how calcium nitrate is prepared by an acid-base reaction.
When anhydrous calcium nitrate is strongly heated, it breaks down to leave a white solid. Identify this white solid and suggest one further observation for this reaction.
The ease with which Group II nitrates undergo thermal decomposition becomes smaller down the group. Explain this pattern.
What does the term standard enthalpy change of hydration, $\Delta H^\circ_{\text{hyd}}$, mean?
Use the data below to calculate the lattice energy, $\Delta H^\circ_{\text{latt}}$, of calcium nitrate, $\text{Ca(NO}_3)_2(s)$. It may help to draw an energy cycle. The data given are: $\Delta H^\circ_{\text{hyd}}(\text{Ca}^{2+}(g)) = -1650\ \text{kJ mol}^{-1}$, $\Delta H^\circ_{\text{hyd}}(\text{NO}_3^{-}(g)) = -314\ \text{kJ mol}^{-1}$, and the enthalpy change of solution for $\text{Ca(NO}_3)_2(s)$ is $-19\ \text{kJ mol}^{-1}$. Calculate $\Delta H^\circ_{\text{latt}}$ for $\text{Ca(NO}_3)_2(s)$.
The standard enthalpy change of hydration for $\text{Ba}^{2+}$, $\Delta H^\circ_{\text{hyd}}(\text{Ba}^{2+}(g))$, is $-1305\ \text{kJ mol}^{-1}$. Suggest an explanation for why the $\Delta H^\circ_{\text{hyd}}$ of the $\text{Ba}^{2+}$ ion is less exothermic than the $\Delta H^\circ_{\text{hyd}}$ of the $\text{Ca}^{2+}$ ion.