In `OF_2`, the number of bond pairs and lone pairs of electrons are respectively,

Options

A. 2,6
B. 2,8
C. 2,10
D. 2,9

Answer

To determine the number of bond pairs and lone pairs of electrons in the molecule OF₂ (oxygen difluoride), we will follow these steps:

### Step 1: Determine the Valence Electrons
- Oxygen (O) has 6 valence electrons.
- Each fluorine (F) atom has 7 valence electrons, and there are 2 fluorine atoms.

**Calculation:**
- Total valence electrons = Valence electrons of O + Valence electrons of 2 F
- Total valence electrons = 6 + (2 × 7) = 6 + 14 = 20 valence electrons.

### Step 2: Identify the Central Atom
- In OF₂, oxygen is the central atom because it is less electronegative than fluorine.

### Step 3: Determine the Hybridization
- To find the hybridization or steric number, we can use the formula:

\[ \text{Steric Number} = \frac{1}{2} \left( \text{V} + \text{M} + \text{C} - \text{A} \right) \]

Where:
- V = number of valence electrons of the central atom (O = 6)
- M = number of monovalent atoms attached (2 F atoms = 2)
- C = positive charge (0 for neutral species)
- A = negative charge (0 for neutral species)

**Calculation:**
- Steric Number = \( \frac{1}{2} (6 + 2 + 0 - 0) = \frac{1}{2} (8) = 4 \)

### Step 4: Determine Bond Pairs and Lone Pairs
- The steric number of 4 indicates that there are 4 regions of electron density around the oxygen atom.
- In OF₂, oxygen forms 2 bonds with the 2 fluorine atoms, which accounts for 2 bond pairs.

**Calculation of Lone Pairs:**
- Total regions of electron density (4) = Bond pairs (2) + Lone pairs (X)
- Therefore, \( 4 = 2 + X \)
- Solving for X gives us \( X = 2 \) lone pairs.

### Step 5: Count the Total Lone Pairs
- Each fluorine atom has 6 remaining valence electrons (since they each use 1 for bonding with oxygen).
- Thus, each fluorine has 3 lone pairs.
- Total lone pairs from fluorine = \( 2 \times 3 = 6 \) lone pairs.

### Step 6: Total Lone Pairs in the Molecule
- Total lone pairs in OF₂ = Lone pairs on O + Lone pairs on F
- Total lone pairs = 2 (on O) + 6 (on 2 F) = 8 lone pairs.

### Final Answer
- The number of bond pairs in OF₂ is 2, and the number of lone pairs is 8.

Thus, the answer is **2 bond pairs and 8 lone pairs**.

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