Chemistry - PERIODIC TABLE Question with Solution | TestHub

Question Explanation: Evaluating energy changes in electron gain processes.

Concept: Electron Gain Enthalpy ( $\Delta {\mathrm{H}}_{e.g}$ ).

Solution: Adding an electron to a cation is always exothermic ( $\Delta {\mathrm{H}}_{\mathrm{e}.\mathrm{g}}<0$ ) because the positive nucleus strongly attracts the negative electron. For neutral atoms, $\Delta {\mathrm{H}}_{\text{e.g }}$ is usually exothermic but can be endothermic for noble gases.

Neutral Atom +e^-→ Anion ( ΔH usually negative).

Cation +e^-→ Neutral Atom ( ΔH always negative / exothermic )

For Na: IE₁ of Na is equal in magnitude to ΔHe.g.of Na⁺ , but opposite in sign.

Final Answer: , ΔHe.g. of a cation is always an exothermic process)