Which of the following element does not show the variable oxidation state ?

Options

A. Fe
B. Mn
C. Cu
D. Zn

Answer

To determine which of the given elements does not show a variable oxidation state, we will analyze the oxidation states of each element: iron, manganese, copper, and zinc.

### Step-by-Step Solution:

1. **Identify the Elements and Their Electronic Configurations**:
- **Iron (Fe)**: Atomic number 26, electronic configuration: [Ar] 3d^6 4s^2
- **Manganese (Mn)**: Atomic number 25, electronic configuration: [Ar] 3d^5 4s^2
- **Copper (Cu)**: Atomic number 29, electronic configuration: [Ar] 3d^10 4s^1
- **Zinc (Zn)**: Atomic number 30, electronic configuration: [Ar] 3d^10 4s^2

2. **Analyze Iron (Fe)**:
- Iron can lose two electrons from the 4s orbital to show a +2 oxidation state.
- It can also lose one electron from the 3d orbital to show a +3 oxidation state.
- Therefore, iron shows variable oxidation states (+2 and +3).

3. **Analyze Manganese (Mn)**:
- Manganese can lose both 4s electrons to show a +2 oxidation state.
- It can further lose electrons from the 3d orbital, showing oxidation states of +3, +4, +5, +6, and +7.
- Thus, manganese also shows variable oxidation states.

4. **Analyze Copper (Cu)**:
- Copper can lose one electron from the 4s orbital to show a +1 oxidation state.
- It can also lose one electron from the 3d orbital to show a +2 oxidation state.
- Therefore, copper exhibits variable oxidation states (+1 and +2).

5. **Analyze Zinc (Zn)**:
- Zinc can lose both electrons from the 4s orbital to show a +2 oxidation state.
- After losing these two electrons, it attains a stable 3d^10 configuration.
- It does not lose any more electrons easily due to the stability of the d10 configuration.
- Thus, zinc only shows the +2 oxidation state and does not exhibit variable oxidation states.

6. **Conclusion**:
- Among the elements analyzed, zinc is the only element that does not show a variable oxidation state. Therefore, the answer is **Zinc (Zn)**.

### Final Answer:
Zinc (Zn) does not show a variable oxidation state.

---