Which moleucle is T-shaped ?

Options

A. `BeF_(2)`
B. `BCI_(3)`
C. `NH_(3)`
D. `CIF_(3)`

Explanation

To determine which molecule is T-shaped, we will analyze the given molecules one by one based on their molecular geometry and steric number.

### Step-by-Step Solution:

1. **Identify the Molecules**: The given molecules are BEF3, BCl3, NH3, and ClF3.

2. **Analyze BEF3**:
- **Valence Electrons**: Beryllium (Be) has 2 valence electrons.
- **Ligands**: There are 3 fluorine (F) atoms bonded to beryllium.
- **Steric Number**: Steric number = number of bonded atoms + number of lone pairs = 3 (bonded) + 0 (lone pairs) = 3.
- **Shape**: With a steric number of 3 and no lone pairs, the shape is **trigonal planar**.

3. **Analyze BCl3**:
- **Valence Electrons**: Boron (B) has 3 valence electrons.
- **Ligands**: There are 3 chlorine (Cl) atoms bonded to boron.
- **Steric Number**: Steric number = 3 (bonded) + 0 (lone pairs) = 3.
- **Shape**: With a steric number of 3 and no lone pairs, the shape is **trigonal planar**.

4. **Analyze NH3**:
- **Valence Electrons**: Nitrogen (N) has 5 valence electrons.
- **Ligands**: There are 3 hydrogen (H) atoms bonded to nitrogen.
- **Lone Pairs**: There is 1 lone pair.
- **Steric Number**: Steric number = 3 (bonded) + 1 (lone pair) = 4.
- **Shape**: With a steric number of 4 and 1 lone pair, the shape is **trigonal pyramidal**.

5. **Analyze ClF3**:
- **Valence Electrons**: Chlorine (Cl) has 7 valence electrons.
- **Ligands**: There are 3 fluorine (F) atoms bonded to chlorine.
- **Lone Pairs**: There are 2 lone pairs.
- **Steric Number**: Steric number = 3 (bonded) + 2 (lone pairs) = 5.
- **Shape**: With a steric number of 5 and 2 lone pairs, the shape is **T-shaped**. The lone pairs occupy equatorial positions to minimize repulsion.

6. **Conclusion**: The molecule that is T-shaped is **ClF3**.

### Final Answer:
The T-shaped molecule is **ClF3**.