Higher oxidation state of manganese in fluoride is `+4 (MnF_(4))` but highest oxidation state in oxides is `+7(Mn_(2)O_(7))` because

Options

A. fluorine is more electronegative than oxygen
B. fluorine does not possess d-orbitals
C. fluorine stabilises lower oxidation state
D. in covalent compounds, fluorine can form single bond only while oxygen forms double bond.

Explanation

To understand why the higher oxidation state of manganese in fluoride is +4 (as in MnF4) while the highest oxidation state in oxides is +7 (as in Mn2O7), we need to analyze the bonding characteristics of fluorine and oxygen.

### Step-by-Step Solution:

1. **Identify the Oxidation States**:
- In MnF4, manganese has an oxidation state of +4.
- In Mn2O7, manganese has an oxidation state of +7.

2. **Bonding Characteristics**:
- Fluorine can only form single bonds due to its electronic configuration. This means that each fluorine atom can only bond with manganese through a single bond.
- Oxygen, on the other hand, has the ability to form double bonds. Each oxygen atom can form two bonds with manganese.

3. **Limitations of Fluorine**:
- Because fluorine can only form single bonds, manganese can only accommodate a limited number of fluorine atoms around it. In MnF4, manganese is bonded to four fluorine atoms, which corresponds to its +4 oxidation state.
- If more fluorine atoms were to be added, steric hindrance or overcrowding would occur, preventing manganese from achieving a higher oxidation state.

4. **Flexibility of Oxygen**:
- In the case of oxides like Mn2O7, manganese can utilize its ability to form double bonds with oxygen. Each manganese atom can form multiple bonds with oxygen, allowing it to achieve a higher oxidation state of +7.
- The structure of Mn2O7 involves two manganese atoms each forming double bonds with oxygen, which stabilizes the higher oxidation state.

5. **Conclusion**:
- The key reason for the difference in oxidation states is the bonding nature of fluorine and oxygen. Fluorine's limitation to single bonds restricts manganese to a +4 oxidation state, while oxygen's ability to form double bonds allows manganese to reach a +7 oxidation state.

### Final Answer:
The higher oxidation state of manganese in fluoride is +4 (MnF4), while the highest oxidation state in oxides is +7 (Mn2O7) because fluorine can only form single bonds, limiting the oxidation state of manganese, whereas oxygen can form double bonds, allowing for a higher oxidation state.