The ionic character of the metal halides MCl , MI,MBr, MF decreases in the order

Options

A. `MF gt MBr gt MI gt MCl `
B. `MI gt MBr gt MF gt MCl `
C. `MF gt MCl gt MBr gt MI `
D. `MBr gt MF gt MI gt MCl `

Explanation

To determine the order of ionic character of the metal halides MCl, MI, MBr, and MF, we can follow these steps:

### Step 1: Understand the Concept of Ionic Character
Ionic character refers to the extent to which a compound exhibits ionic bonding as opposed to covalent bonding. Compounds with higher ionic character have a greater tendency to dissociate into ions in solution.

### Step 2: Analyze the Halides
The halides in question are:
- MF (Metal Fluoride)
- MCl (Metal Chloride)
- MBr (Metal Bromide)
- MI (Metal Iodide)

### Step 3: Consider the Size of the Halide Ions
The size of the halide ions increases as we move down the group in the periodic table:
- Fluoride (F⁻) < Chloride (Cl⁻) < Bromide (Br⁻) < Iodide (I⁻)

### Step 4: Apply Fajans' Rules
According to Fajans' rules, the ionic character of a compound is influenced by the polarizability of the anion and the charge density of the cation:
- Smaller anions (like F⁻) are less polarizable and tend to form more ionic bonds.
- Larger anions (like I⁻) are more polarizable and tend to form more covalent bonds.

### Step 5: Determine the Order of Ionic Character
Based on the size and polarizability of the halide ions:
- MF (Metal Fluoride) will have the highest ionic character because F⁻ is the smallest and least polarizable.
- MCl (Metal Chloride) will have a lower ionic character than MF.
- MBr (Metal Bromide) will have even lower ionic character than MCl.
- MI (Metal Iodide) will have the lowest ionic character because I⁻ is the largest and most polarizable.

### Conclusion: Order of Ionic Character
Thus, the order of ionic character from highest to lowest is:
**MF > MCl > MBr > MI**

### Final Answer
The answer to the question is: **MF > MCl > MBr > MI**