Which of the following molecule/species is having minimum number of lone pair on its central atom?

Options

A. `BrF_3`
B. `BrF_(4)^(-)`
C. `XeF_(5)^(+)`
D. `I_(3)^(-)`

Answer

To determine which molecule or species has the minimum number of lone pairs on its central atom, we will analyze the lone pairs present in each of the given species.

### Step-by-Step Solution:

1. **Identify the Central Atom**:
- For each molecule, identify the central atom.
- Examples:
- In BrF3, the central atom is Bromine (Br).
- In BrF4-, the central atom is also Bromine (Br).
- In XeF5+, the central atom is Xenon (Xe).
- In I3-, the central atom is Iodine (I).

2. **Count Valence Electrons**:
- Determine the number of valence electrons for the central atom.
- Bromine (Br) has 7 valence electrons.
- Xenon (Xe) has 8 valence electrons.
- Iodine (I) has 7 valence electrons.

3. **Account for Bonds**:
- Count the number of bonds formed with surrounding atoms.
- For BrF3: Bromine forms 3 bonds with Fluorine (3 electrons used).
- For BrF4-: Bromine forms 4 bonds with Fluorine (4 electrons used) and gains an extra electron due to the negative charge.
- For XeF5+: Xenon forms 5 bonds with Fluorine (5 electrons used) and loses an electron due to the positive charge.
- For I3-: Iodine forms 2 bonds with Iodine atoms and has a negative charge, which adds an electron.

4. **Calculate Lone Pairs**:
- Use the formula:
\[ \text{Lone pairs} = \frac{\text{Valence electrons} - \text{Number of bonds}}{2} \]
- For BrF3:
\[ \text{Lone pairs} = \frac{7 - 3}{2} = 2 \]
- For BrF4-:
\[ \text{Lone pairs} = \frac{8 - 4}{2} = 2 \]
- For XeF5+:
\[ \text{Lone pairs} = \frac{8 - 5}{2} = 1.5 \text{ (round down to 1)} \]
- For I3-:
\[ \text{Lone pairs} = \frac{8 - 2}{2} = 3 \]

5. **Compare the Lone Pairs**:
- BrF3: 2 lone pairs
- BrF4-: 2 lone pairs
- XeF5+: 1 lone pair
- I3-: 3 lone pairs

6. **Conclusion**:
- The species with the minimum number of lone pairs on its central atom is **XeF5+**, which has 1 lone pair.

### Final Answer:
**XeF5+ has the minimum number of lone pairs on its central atom.**