Which of the following has tendency to act as an oxidising agent?

Options

A. `Ce^(4+)`
B. `Sm^(2+)`
C. `Lu^(3+)`
D. `Gd^(3+)`

Explanation

To determine which of the given species has the tendency to act as an oxidizing agent, we need to analyze the oxidation states and electronic configurations of the elements provided: Ce (Cerium), Sm (Samarium), Lu (Lutetium), and Gd (Gadolinium).

### Step-by-Step Solution:

1. **Understand the Concept of Oxidizing Agents**:
- An oxidizing agent is a substance that can accept electrons from another species, thereby oxidizing it. In the process, the oxidizing agent itself gets reduced.

2. **Identify the Given Species and Their Oxidation States**:
- The species we need to analyze are:
- Ce (Cerium) in the +4 oxidation state (Ce⁴⁺)
- Sm (Samarium) in the +2 oxidation state (Sm²⁺)
- Lu (Lutetium) in the +3 oxidation state (Lu³⁺)
- Gd (Gadolinium) in the +3 oxidation state (Gd³⁺)

3. **Analyze the Electronic Configurations**:
- **Cerium (Ce)**: Atomic number 58, configuration: [Xe] 4f¹ 5d¹ 6s²
- Ce⁴⁺: After losing 4 electrons, it becomes [Xe] 4f⁰ 5d⁰ 6s⁰. It has reached its maximum oxidation state and cannot be oxidized further, meaning it can act as an oxidizing agent.

- **Samarium (Sm)**: Atomic number 62, configuration: [Xe] 4f⁶ 6s²
- Sm²⁺: After losing 2 electrons, it becomes [Xe] 4f⁶ 6s⁰. It still has available electrons in the 4f orbital, which means it can potentially be reduced but does not have a strong tendency to act as an oxidizing agent.

- **Lutetium (Lu)**: Atomic number 71, configuration: [Xe] 4f¹⁴ 5d¹ 6s²
- Lu³⁺: After losing 3 electrons, it becomes [Xe] 4f¹⁴ 5d⁰ 6s⁰. With a completely filled 4f orbital, it does not have a tendency to act as an oxidizing agent as it is stable in this state.

- **Gadolinium (Gd)**: Atomic number 64, configuration: [Xe] 4f⁷ 5d¹ 6s²
- Gd³⁺: After losing 3 electrons, it becomes [Xe] 4f⁷ 5d⁰ 6s⁰. The half-filled 4f orbital is relatively stable, and while it can be reduced, it does not have a strong tendency to act as an oxidizing agent.

4. **Conclusion**:
- Among the species analyzed, **Ce⁴⁺** (Cerium) is the only one that has a strong tendency to act as an oxidizing agent due to its inability to be oxidized further and its capacity to accept electrons.

### Final Answer:
**Cerium (Ce⁴⁺) has the tendency to act as an oxidizing agent.**