Which of the following process requires the largest amount of energy ?

Options

A. `Al_((g))rarrAl^(o+) +e^(-)`
B. `Al_((g))^(2+)rarrAl^(3+)+e^(-)`
C. `Al_((g))^(o+) rarr Al^(2+) + e^(-)`
D. All require same amount of energy

Explanation

To determine which of the following processes requires the largest amount of energy, we need to analyze the successive ionization energies of aluminum (Al).

### Step-by-Step Solution:

1. **Understand Ionization Energy**:
Ionization energy is the energy required to remove an electron from an atom in its gaseous state. The first ionization energy (IE1) is the energy needed to remove the first electron, the second ionization energy (IE2) is for removing the second electron, and so on.

2. **Identify the Processes**:
The processes given involve the successive ionization of aluminum:
- Process 1: Al(g) → Al⁺(g) + e⁻ (IE1)
- Process 2: Al⁺(g) → Al²⁺(g) + e⁻ (IE2)
- Process 3: Al²⁺(g) → Al³⁺(g) + e⁻ (IE3)

3. **Analyze the Trend in Ionization Energies**:
Generally, the ionization energy increases with each successive electron removed. This is because:
- As electrons are removed, the positive charge of the nucleus has a stronger effect on the remaining electrons, leading to a decrease in atomic size.
- The order of ionization energies is: IE1 < IE2 < IE3.

4. **Determine Which Process Requires the Most Energy**:
Since IE3 corresponds to the removal of the third electron from Al²⁺, and we know that IE3 is greater than both IE1 and IE2, it requires the largest amount of energy.

5. **Conclusion**:
Therefore, the process that requires the largest amount of energy is the third ionization process: Al²⁺(g) → Al³⁺(g) + e⁻, which corresponds to the third ionization energy (IE3).

### Final Answer:
The process that requires the largest amount of energy is the third ionization energy (IE3).

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