Number of lone electron pairs around central atom in `BrF_5` is

Explanation

To determine the number of lone electron pairs around the central atom in \( \text{BrF}_5 \), we can follow these steps:

### Step 1: Identify the Central Atom
The central atom in \( \text{BrF}_5 \) is Bromine (Br). This is because it is bonded to multiple Fluorine (F) atoms.

**Hint:** The central atom is typically the one that can form the most bonds or is less electronegative compared to surrounding atoms.

### Step 2: Determine the Valence Electrons
Bromine is in Group 17 of the periodic table, which means it has 7 valence electrons. Each Fluorine atom also has 7 valence electrons.

**Hint:** Check the periodic table to find the group number, which indicates the number of valence electrons.

### Step 3: Draw the Lewis Structure
In the Lewis structure of \( \text{BrF}_5 \), Bromine will form bonds with 5 Fluorine atoms. Each bond uses 1 valence electron from Bromine. Therefore, Bromine will use 5 of its 7 valence electrons to bond with the 5 Fluorine atoms.

**Hint:** Remember that each bond consists of 2 electrons (one from each atom), but we only count the electrons used from the central atom.

### Step 4: Calculate Remaining Electrons
After forming 5 bonds, Bromine has used 5 of its 7 valence electrons, leaving it with 2 electrons that are not used in bonding.

**Hint:** Subtract the number of electrons used in bonding from the total valence electrons to find the remaining electrons.

### Step 5: Determine Lone Pairs
The 2 remaining electrons on Bromine form 1 lone pair (since a lone pair consists of 2 electrons).

**Hint:** A lone pair is defined as a pair of valence electrons that are not shared with another atom.

### Conclusion
Thus, the number of lone electron pairs around the central atom in \( \text{BrF}_5 \) is **1**.

**Final Answer:** 1 lone electron pair.