Calcium has a second ionisation energy of $1150\ \text{kJ mol}^{-1}$. Which equation correctly shows this statement?
- A$\text{Ca}(\text{g}) \rightarrow \text{Ca}^{2+}(\text{g}) + 2\text{e}^- ; \ \Delta H^\circ = +1150\ \text{kJ mol}^{-1}$
- B$\text{Ca}^+(\text{g}) \rightarrow \text{Ca}^{2+}(\text{g}) + \text{e}^- ; \ \Delta H^\circ = +1150\ \text{kJ mol}^{-1}$
- C$\text{Ca}^+(\text{g}) \rightarrow \text{Ca}^{2+}(\text{g}) + \text{e}^- ; \ \Delta H^\circ = -1150\ \text{kJ mol}^{-1}$
- D$\text{Ca}(\text{g}) \rightarrow \text{Ca}^{2+}(\text{g}) + 2\text{e}^- ; \ \Delta H^\circ = -1150\ \text{kJ mol}^{-1}$