Which of the process requires largest energy among them?

Options

A. `Al (g) to Al^(+) (g) + e^-`
B. `Al^^(2+) gt Al^(3+) (g) + e^-`
C. `Al^(+)(g) to Al^(2+) (g) + e^(-)`
D. All the processes require same amount of energy

Explanation

To determine which process requires the largest energy among the given options, we need to understand the concept of ionization energy. Ionization energy is the energy required to remove an electron from an isolated gaseous atom.

### Step-by-Step Solution:

1. **Understanding Ionization Energy**:
- Ionization energy (IE) is defined as the amount of energy required to remove an electron from an atom in its gaseous state.
- The first ionization energy (IE1) is the energy required to remove the first electron, the second ionization energy (IE2) is for the second electron, and so on.

2. **Analyzing the Element**:
- Let's take aluminum (Al) as an example, which has an atomic number of 13.
- Its electronic configuration is: 1s² 2s² 2p⁶ 3s² 3p¹.
- The outermost electrons are in the 3s and 3p subshells.

3. **Removing Electrons**:
- When we remove the first electron (IE1), it comes from the 3p subshell, which is relatively easier because it is not fully filled.
- For the second electron (IE2), we are removing from the 3s subshell, which is fully filled with 2 electrons. This requires more energy because the electron is held more tightly due to increased effective nuclear charge.

4. **Comparing Ionization Energies**:
- IE1 < IE2 < IE3:
- The first ionization energy (IE1) is the least because it is the easiest to remove an electron from a partially filled subshell.
- The second ionization energy (IE2) is greater because it involves removing an electron from a filled subshell.
- The third ionization energy (IE3) will be even higher as it involves removing an electron from a more stable configuration.

5. **Conclusion**:
- Among the processes of removing electrons (IE1, IE2, IE3), the second ionization energy (IE2) requires the largest energy because it involves removing an electron from a filled subshell, which is more stable and thus requires more energy to ionize.

### Final Answer:
The process that requires the largest energy is the second ionization energy (IE2).