A molecule `XY_(2)` contains two `sigma` bonds two `pi` bond and one lone pair of electrons in the valence shell of `X`. The arrangement of lone pair as well as bond pairs is

Options

A. square pyramidal
B. linear
C. Trigonal planar
D. unpredictable

Answer

To solve the problem regarding the molecule \( XY_2 \) with the given characteristics, we will follow these steps:

### Step 1: Identify the bonds and lone pairs
The molecule \( XY_2 \) contains:
- 2 sigma (\( \sigma \)) bonds
- 2 pi (\( \pi \)) bonds
- 1 lone pair of electrons on atom \( X \)

### Step 2: Determine the steric number
The steric number is calculated by adding the number of sigma bonds and the number of lone pairs:
- Number of sigma bonds = 2
- Number of lone pairs = 1

Thus, the steric number (SN) is:
\[ \text{Steric Number} = \text{Number of } \sigma \text{ bonds} + \text{Number of lone pairs} = 2 + 1 = 3 \]

### Step 3: Determine the hybridization
The hybridization can be determined from the steric number:
- A steric number of 3 corresponds to \( sp^2 \) hybridization.

### Step 4: Determine the molecular geometry
For \( sp^2 \) hybridization, the arrangement of electron pairs (both bonding and lone pairs) is trigonal planar. However, because there is one lone pair, the molecular geometry will be affected:
- The presence of a lone pair will result in a bent or angular shape.

### Step 5: Conclusion
The arrangement of lone pairs and bond pairs in the molecule \( XY_2 \) is:
- **Electron pair geometry**: Trigonal planar
- **Molecular geometry**: Bent (due to the lone pair)

### Final Answer:
The arrangement of lone pairs and bond pairs in the molecule \( XY_2 \) is trigonal planar for electron pairs and bent for molecular geometry.

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