Which of the following ions does not have pseudoinert gas configuration ?

Options

A. `Zn^(2+)`
B. `Sc^(3+)`
C. `Ag^(+)`
D. `Cd^(2+)`.

Answer

To determine which of the following ions does not have a pseudo-inert gas configuration, we first need to understand what a pseudo-inert gas configuration is. A pseudo-inert gas configuration occurs when an ion has a total of 18 electrons in its highest energy level (valence shell) instead of the usual 8 electrons found in a noble gas configuration. This configuration is typically observed in transition metals and involves the presence of d-block electrons.

### Step-by-Step Solution:

1. **Identify the Ions**: We need to analyze the given ions. The ions mentioned are Zn²⁺, Ag⁺, and Cd²⁺.

2. **Determine the Atomic Numbers**:
- **Zinc (Zn)**: Atomic number = 30
- **Silver (Ag)**: Atomic number = 47
- **Cadmium (Cd)**: Atomic number = 48

3. **Calculate the Electron Configuration for Each Ion**:
- **For Zn²⁺**:
- Atomic number = 30
- Zn²⁺ has lost 2 electrons: 30 - 2 = 28 electrons.
- Electron configuration: [Ar] 3d¹⁰ (18 electrons in the outer shell).
- This configuration is pseudo-inert gas configuration.

- **For Ag⁺**:
- Atomic number = 47
- Ag⁺ has lost 1 electron: 47 - 1 = 46 electrons.
- Electron configuration: [Kr] 4d¹⁰ (18 electrons in the outer shell).
- This configuration is also a pseudo-inert gas configuration.

- **For Cd²⁺**:
- Atomic number = 48
- Cd²⁺ has lost 2 electrons: 48 - 2 = 46 electrons.
- Electron configuration: [Kr] 4d¹⁰ (18 electrons in the outer shell).
- This configuration is again a pseudo-inert gas configuration.

4. **Identify the Ion Without Pseudo-Inert Gas Configuration**:
- Among the ions analyzed, Zn²⁺, Ag⁺, and Cd²⁺ all have pseudo-inert gas configurations.
- However, if we consider Sc³⁺ (which was mentioned in the video), it does not have a pseudo-inert gas configuration because it has only 3 electrons in the outer shell (3d¹).

5. **Conclusion**:
- The ion that does not have a pseudo-inert gas configuration is **Sc³⁺**.

### Final Answer:
The ion that does not have a pseudo-inert gas configuration is **Sc³⁺**.