Which of the following ions does not have the configuration of argon ?

Options

A. `Cl^(-)`
B. `K^(+)`
C. `Ca^(2+)`
D. `I^(-)`

Explanation

To determine which of the following ions does not have the electron configuration of argon, we first need to understand the electron configuration of argon and how to find the electron configurations of the given ions.

### Step-by-Step Solution:

1. **Identify the Atomic Number of Argon**:
- Argon (Ar) has an atomic number of 18. This means that a neutral argon atom has 18 electrons.

2. **Determine the Electron Configuration of Argon**:
- The electron configuration of argon is:
\[ 1s^2 2s^2 2p^6 3s^2 3p^6 \]

3. **Analyze the Given Ions**:
- We need to check the electron configurations of the ions provided in the question. Let's assume the ions are Chlorine (Cl⁻), Potassium (K⁺), Calcium (Ca²⁺), and Iodine (I⁻).

4. **Check Each Ion**:
- **Chlorine (Cl⁻)**:
- Atomic number of Cl = 17.
- Cl⁻ gains one electron, so it has 18 electrons.
- Configuration: Same as Ar.
- **Potassium (K⁺)**:
- Atomic number of K = 19.
- K⁺ loses one electron, so it has 18 electrons.
- Configuration: Same as Ar.
- **Calcium (Ca²⁺)**:
- Atomic number of Ca = 20.
- Ca²⁺ loses two electrons, so it has 18 electrons.
- Configuration: Same as Ar.
- **Iodine (I⁻)**:
- Atomic number of I = 53.
- I⁻ gains one electron, so it has 54 electrons.
- Configuration: Same as Xe (Xenon), not Ar.

5. **Conclusion**:
- The ion that does not have the electron configuration of argon is **I⁻** (Iodine).

### Final Answer:
The ion that does not have the configuration of argon is **I⁻**.