Which of the following have maximum and minimum ionic character out of MnO, `MnF_2,MnO_2, Mn_2O_7` ?

Options

A. `MNO,Mn_2O_7` respectively
B. `MnF_2, Mn_2O_7` resectively
C. `MnO_2, MnO` respectively
D. `Mn_2O_7, MnO` respectively

Explanation

To determine which of the compounds MnO, MnF2, MnO2, and Mn2O7 has the maximum and minimum ionic character, we will analyze the oxidation states of manganese in each compound and apply the principles of ionic and covalent character.

### Step-by-Step Solution:

1. **Identify the Oxidation States:**
- **MnO:**
- Let the oxidation state of Mn be \( x \).
- The oxidation state of O is \(-2\).
- Equation: \( x - 2 = 0 \) → \( x = +2 \).
- **MnF2:**
- Let the oxidation state of Mn be \( x \).
- The oxidation state of F is \(-1\).
- Equation: \( x + 2(-1) = 0 \) → \( x = +2 \).
- **MnO2:**
- Let the oxidation state of Mn be \( x \).
- The oxidation state of O is \(-2\).
- Equation: \( x + 2(-2) = 0 \) → \( x = +4 \).
- **Mn2O7:**
- Let the oxidation state of Mn be \( x \).
- The oxidation state of O is \(-2\).
- Equation: \( 2x + 7(-2) = 0 \) → \( 2x - 14 = 0 \) → \( x = +7 \).

2. **Analyze Ionic and Covalent Character:**
- According to Fajans' rules, the covalent character is directly proportional to the charge on the cation and the size of the anion. Conversely, the ionic character is inversely proportional to the covalent character.
- Higher charge on the cation leads to greater covalent character, which results in lower ionic character.
- Larger anion size also increases covalent character, reducing ionic character.

3. **Determine Ionic Character for Each Compound:**
- **MnO:**
- Charge on Mn = +2, Anion = O2- (larger size).
- **MnF2:**
- Charge on Mn = +2, Anion = F- (smaller size).
- **MnO2:**
- Charge on Mn = +4, Anion = O2- (larger size).
- **Mn2O7:**
- Charge on Mn = +7, Anion = O2- (larger size).

4. **Comparing Ionic Characters:**
- **Maximum Ionic Character:**
- Between MnO and MnF2, both have Mn in +2 state, but F- is smaller than O2-, leading to less covalent character in MnF2. Therefore, **MnF2 has the maximum ionic character**.
- **Minimum Ionic Character:**
- Mn2O7 has the highest charge on Mn (+7), leading to the maximum covalent character and thus the **minimum ionic character**.

### Conclusion:
- **Maximum Ionic Character:** MnF2
- **Minimum Ionic Character:** Mn2O7