Various oxidation states of few elements are mentioned. Which of the options is not correctly matched ?

Options

A. Phosphorus: +3 to +5
B. Nitrogen : +1 to +5
C. Iodine : -1 to +7
D. Chromium : -3 to +6

Explanation

To determine which oxidation states of the given elements are not correctly matched, we will analyze the oxidation states of phosphorus, nitrogen, iodine, and chromium.

### Step-by-Step Solution:

1. **Phosphorus (P)**:
- Atomic number: 15
- Electron configuration: 1s² 2s² 2p⁶ 3s² 3p³
- Valence electrons: 5 (3 from 3p and 2 from 3s)
- Possible oxidation states: +3 (by losing 3 electrons) and +5 (by losing all 5 valence electrons).
- **Conclusion**: The oxidation states for phosphorus are correctly stated.

2. **Nitrogen (N)**:
- Atomic number: 7
- Electron configuration: 1s² 2s² 2p³
- Valence electrons: 5 (3 from 2p and 2 from 2s)
- Possible oxidation states: +1 (by losing 1 electron), +3 (by losing 3 electrons), and +5 (by losing all 5 valence electrons).
- **Conclusion**: The oxidation states for nitrogen are correctly stated.

3. **Iodine (I)**:
- Atomic number: 53
- Electron configuration: [Kr] 5s² 5p⁵
- Valence electrons: 7 (5 from 5p and 2 from 5s)
- Possible oxidation states: -1 (by gaining 1 electron to achieve a stable octet), and +7 (by losing all 7 valence electrons).
- **Conclusion**: The oxidation states for iodine are correctly stated.

4. **Chromium (Cr)**:
- Atomic number: 24
- Electron configuration: [Ar] 4s¹ 3d⁵ (exceptional configuration)
- Valence electrons: 6 (1 from 4s and 5 from 3d)
- Possible oxidation states: +6 (by losing all 6 valence electrons) and +3 (by losing 3 electrons). However, it cannot exhibit a -3 oxidation state because it cannot gain 3 electrons.
- **Conclusion**: The oxidation states for chromium are incorrectly stated as it cannot have a -3 oxidation state.

### Final Answer:
The option that is not correctly matched is the oxidation state of chromium, which cannot exhibit a -3 oxidation state.

---