Which of the following transitions involves maximum amount of energy?

Options

A. `M `to`M^(+)+e^(-)`
B. `M^(-)`to`M^(+)+2e^(-)`
C. `M^(2+)`to`M^(3+)+e^(-)`
D. `M^(+)`to`M^(2+)+e^(-)`

Explanation

To determine which transition involves the maximum amount of energy, we will analyze each transition step by step.

### Step 1: Analyze the transitions

1. **Transition A: M to M+**
- In this transition, a neutral atom (M) loses one electron to become a cation (M+). This process requires energy, known as ionization energy, but it is relatively moderate since only one electron is being removed.

2. **Transition B: M- to M+**
- Here, we have an anion (M-) that has gained an extra electron. When it loses two electrons to become M+, it will require less energy compared to the first transition because the removal of the extra electron (the one that was added) is easier. Thus, this transition involves the least amount of energy.

3. **Transition C: M2+ to M3+**
- In this case, a divalent cation (M2+) loses one electron to become a trivalent cation (M3+). Since M2+ has already lost two electrons, the effective nuclear charge on the remaining electrons is higher, which means that removing another electron will require more energy than in the previous cases.

4. **Transition D: M+ to M2+**
- This transition involves a monovalent cation (M+) losing one electron to become a divalent cation (M2+). Similar to Transition C, this also requires energy, but it will be less than Transition C because M+ has only lost one electron compared to M2+.

### Step 2: Compare the energy requirements

- **Transition B (M- to M+)** requires the least energy.
- **Transition A (M to M+)** requires more energy than Transition B.
- **Transition D (M+ to M2+)** requires more energy than Transition A but less than Transition C.
- **Transition C (M2+ to M3+)** requires the most energy due to the increased effective nuclear charge and the fact that it is removing an electron from a cation that has already lost two electrons.

### Conclusion

The transition that involves the maximum amount of energy is **Transition C: M2+ to M3+**.

### Final Answer
**The correct option is Transition C (M2+ to M3+).**

---