In which of the following process highest energy is absorbed?

Options

A. `Cu to Cu^+`
B. `Br to Br^-`
C. `I to I^-`
D. `Li to Li^+`

Answer

To determine which process absorbs the highest energy, we need to analyze the energy changes involved in each of the given processes.

### Step-by-Step Solution:

1. **Identify the Processes**:
- Process 1: Copper (Cu) to Copper ion (Cu⁺)
- Process 2: Bromine (Br) to Bromine ion (Br⁻)
- Process 3: Iodine (I) to Iodine ion (I⁻)
- Process 4: Lithium (Li) to Lithium ion (Li⁺)

2. **Analyze Process 1 (Cu to Cu⁺)**:
- Copper is an electropositive element and loses one electron to form Cu⁺.
- The ionization energy required to remove an electron from Cu is relatively high due to the effective nuclear charge and poor shielding effect of the d-orbitals.
- Therefore, this process absorbs a significant amount of energy.

3. **Analyze Process 2 (Br to Br⁻)**:
- Bromine gains an electron to form Br⁻.
- This process releases energy, as it involves electron gain enthalpy.
- Thus, it does not absorb energy.

4. **Analyze Process 3 (I to I⁻)**:
- Similar to bromine, iodine also gains an electron to form I⁻.
- This process also releases energy, meaning it does not absorb energy.

5. **Analyze Process 4 (Li to Li⁺)**:
- Lithium, being an electropositive element, loses an electron to form Li⁺.
- The ionization energy for lithium is lower than that of copper, hence it absorbs less energy compared to the copper process.

6. **Comparison of Energy Absorption**:
- Between the processes that involve absorption of energy (Cu to Cu⁺ and Li to Li⁺), the process of Cu to Cu⁺ requires more energy due to its higher ionization energy.

7. **Conclusion**:
- The process that absorbs the highest energy is the conversion of Copper (Cu) to Copper ion (Cu⁺).

### Final Answer:
**The highest energy is absorbed in the process of converting Copper (Cu) to Copper ion (Cu⁺).**