Which element does not show variable oxidation state ?

Options

A. Sc
B. V
C. Fe
D. Hg

Answer

To determine which element does not show a variable oxidation state, we will analyze the oxidation states of the given elements: scandium, titanium, vanadium, iron, and mercury.

### Step-by-Step Solution:

1. **Identify the Elements and Their Atomic Numbers**:
- Scandium (Sc), Atomic Number = 21
- Titanium (Ti), Atomic Number = 22
- Vanadium (V), Atomic Number = 23
- Iron (Fe), Atomic Number = 26
- Mercury (Hg), Atomic Number = 80

2. **Write the Electronic Configuration**:
- Scandium: [Ar] 3d¹⁴s²
- Titanium: [Ar] 3d²4s²
- Vanadium: [Ar] 3d³4s²
- Iron: [Ar] 3d⁶4s²
- Mercury: [Xe] 4f¹⁴5d¹⁰6s²

3. **Determine the Common Oxidation States**:
- **Scandium (Sc)**: Primarily shows +3 oxidation state.
- **Titanium (Ti)**: Can show +2, +3, and +4 oxidation states.
- **Vanadium (V)**: Can show +2, +3, +4, and +5 oxidation states.
- **Iron (Fe)**: Can show +2, +3, +4, +5, and +6 oxidation states.
- **Mercury (Hg)**: Can show +1 and +2 oxidation states.

4. **Analyze the Results**:
- Scandium is unique among these elements as it predominantly exhibits only one oxidation state, which is +3.
- The other elements (Ti, V, Fe, and Hg) exhibit multiple oxidation states.

5. **Conclusion**:
- The element that does not show a variable oxidation state is **Scandium (Sc)**.

### Final Answer:
**Scandium (Sc)** does not show variable oxidation states.

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