Question

Which transition involves maximum amount of energy?

(a) $M^- (g) \longrightarrow M(g) + e$

(b) $M^- (g) \longrightarrow M^+ (g) + 2e$

(c) $M^+ (g) \longrightarrow M^{2+} (g) + e$

(d) $M^{2+} (g) \longrightarrow M^{3+} (g) + e$

Answer 1

We have to find out among the following options which transition involves maximum amount of energy.

What is ionization energy ?

The minimum of energy required to remove an electron from the outermost orbit of an isolated gaseous atom is known as ionization enthalpy.

here noticeable point is that first ionization enthalpy is lower than the second ionization enthalpy and second ionization enthalpy is lower much lower than 3rd ionization enthalpy.

i.e., I.E₃ > I.E₂ > I.E₁ ...(1)

here first two options doesn't will be answer, because in both options, the outermost orbit of the given gaseous atom has an extra electron, so it can easily be ejected from its orbit.

and let's observe options (c) and (d), from equation (1), it is clear that energy involved in transition ocurred in option (d) is much higher than that of option (c). hence, maximum amount of energy involved in option (d).

Therefore the correct option is (d), M²⁺ (g) => M³⁺ (g) + e⁻