In which of the following elements `+3` oxidation state is more stable than `+5`?

Options

A. `P`
B. `As`
C. `N`
D. `Bi`

Answer

To determine which of the given elements has a more stable +3 oxidation state compared to the +5 oxidation state, we need to analyze the elements: phosphorus (P), arsenic (As), nitrogen (N), and bismuth (Bi).

### Step-by-Step Solution:

1. **Understanding Oxidation States**:
- Oxidation states refer to the degree of oxidation of an atom in a compound. The +3 and +5 oxidation states indicate the loss of three and five electrons, respectively.

2. **Trends in the Periodic Table**:
- As we move down a group in the periodic table, the stability of lower oxidation states generally increases. This is due to the inert pair effect, where the s-electrons of the outermost shell are less likely to participate in bonding.

3. **Analyzing Each Element**:
- **Nitrogen (N)**: Common oxidation states are -3, +1, +2, +3, +4, and +5. The +5 state is stable due to its ability to form strong bonds, but +3 is also stable.
- **Phosphorus (P)**: Common oxidation states are -3, +3, and +5. The +3 state is more stable than +5 due to the larger atomic size and lower electronegativity.
- **Arsenic (As)**: Common oxidation states are -3, +3, and +5. Similar to phosphorus, the +3 state is more stable than +5.
- **Bismuth (Bi)**: Common oxidation states are +3 and +5. The +3 state is more stable due to the inert pair effect.

4. **Conclusion**:
- Among the elements given, both phosphorus (P) and arsenic (As) have a more stable +3 oxidation state compared to +5. However, the trend becomes more pronounced as we move down the group, making arsenic a better candidate for stability in the +3 state over +5.

### Final Answer:
The elements in which the +3 oxidation state is more stable than +5 are **Phosphorus (P)** and **Arsenic (As)**.