Which of the following is the correct and increasing order of lone pair of electrons on the central atom?

Options

A. `IF_(7), lt IF_(5) lt CIF_(3) lt XeF_(2)`
B. `IF_(7) lt XeF_(2) lt CIF_(2) lt IF_(5)`
C. `IF_(7) lt CIF_(3) lt XeF_(2) lt IF_(5)`
D. `IF_(7) lt XeF_(2) lt IF_(5) lt CIF_(3)`

Answer

To determine the correct increasing order of lone pairs of electrons on the central atom for the given compounds (IF7, IF5, ClF3, and XeF2), we will follow these steps:

### Step-by-Step Solution:

1. **Identify the Central Atom and Valence Electrons**:
- For each molecule, identify the central atom and count the total number of valence electrons.
- **IF7**: Iodine (I) is the central atom with 7 valence electrons.
- **IF5**: Iodine (I) is the central atom with 7 valence electrons.
- **ClF3**: Chlorine (Cl) is the central atom with 7 valence electrons.
- **XeF2**: Xenon (Xe) is the central atom with 8 valence electrons.

2. **Determine the Number of Bonds**:
- Count how many bonds each central atom forms with surrounding fluorine atoms.
- **IF7**: Forms 7 bonds (1 I-F bond for each of the 7 fluorine atoms).
- **IF5**: Forms 5 bonds (1 I-F bond for each of the 5 fluorine atoms).
- **ClF3**: Forms 3 bonds (1 Cl-F bond for each of the 3 fluorine atoms).
- **XeF2**: Forms 2 bonds (1 Xe-F bond for each of the 2 fluorine atoms).

3. **Calculate Lone Pairs**:
- Subtract the number of bonds from the total valence electrons to find the number of lone pairs.
- **IF7**: 7 valence electrons - 7 bonds = 0 lone pairs.
- **IF5**: 7 valence electrons - 5 bonds = 1 lone pair.
- **ClF3**: 7 valence electrons - 3 bonds = 4 electrons left, which means 2 lone pairs (4/2 = 2).
- **XeF2**: 8 valence electrons - 2 bonds = 6 electrons left, which means 3 lone pairs (6/2 = 3).

4. **Arrange in Increasing Order**:
- Now, we can arrange the compounds based on the number of lone pairs:
- IF7: 0 lone pairs
- IF5: 1 lone pair
- ClF3: 2 lone pairs
- XeF2: 3 lone pairs
- Therefore, the increasing order of lone pairs is: **IF7 < IF5 < ClF3 < XeF2**.

### Final Answer:
The correct increasing order of lone pairs of electrons on the central atom is:
**IF7 < IF5 < ClF3 < XeF2**.