The ionization process for which ionization energy is measured is represented by which of the following equations? (M = any metal)
- M(g) → M⁻(g) + e⁻
- M⁺(g) + e⁻ → M(g)
- M(g) → M⁺(g) + e⁻
- M⁺(g) + e⁻ → M(s)
- M(s) → M⁺(aq) + e⁻