The first ionization potential of gaseous Sodium () is . What is the absolute magnitude of the elect — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

The ionization of $Na$ is given by $Na_{(g)} \rightarrow Na^+_{(g)} + e^- \ (\Delta H = +5.1 \text{ eV})$. The electron gain of the $Na^+$ ion is the exact reverse reaction: $Na^+_{(g)} + e^- \rightarrow Na_{(g)}$. According to Hess's Law, the enthalpy change for the reverse reaction is equal in magnitude but opposite in sign ($\Delta H = -5.1 \text{ eV}$). The absolute magnitude is therefore $5.1$.