Europium `(Eu)` and Terbium `(Tb)` attain stable `4f^(7)` configuration by exhibiting oxidation states of

Options

A. `+2` and `+4`
B. `+3` and `+4`
C. `+2` and `+3`
D. `+1` and `+3`

Answer

To determine the oxidation states of Europium (Eu) and Terbium (Tb) that allow them to achieve a stable 4f^7 configuration, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Electron Configuration**:
- Europium (Eu) has the electron configuration: [Xe] 4f^7 6s^2.
- Terbium (Tb) has the electron configuration: [Xe] 4f^9 6s^2.

2. **Determine the Stable Configuration**:
- The stable configuration we want for both elements is 4f^7.

3. **Calculate the Oxidation State for Europium**:
- To achieve the 4f^7 configuration, Europium needs to lose its two 6s electrons.
- Therefore, the oxidation state of Europium when it attains the 4f^7 configuration is +2.

4. **Calculate the Oxidation State for Terbium**:
- To achieve the 4f^7 configuration, Terbium needs to lose the two 6s electrons and also two electrons from the 4f orbital.
- Thus, the oxidation state of Terbium when it attains the 4f^7 configuration is +4.

5. **Final Answer**:
- The oxidation states required for Europium and Terbium to reach the stable 4f^7 configuration are +2 and +4, respectively.

### Summary:
- **Europium (Eu)**: Oxidation state +2
- **Terbium (Tb)**: Oxidation state +4