The geometry with respect ot the central atom of the following molecules are
`N(SiH_(3))_(3), Me_(3)N , (SiH_(3))_(3) P`

Options

A. Planar, pyramidal , planar
B. planar,pyramidal, pyramidal
C. pyramidal,pyramidal,pyramidal
D. pyramidal,planar,pyramidal

Answer

To determine the geometry with respect to the central atom of the molecules \( N(SiH_3)_3 \), \( Me_3N \), and \( (SiH_3)_3P \), we will analyze each molecule step by step.

### Step 1: Analyze \( N(SiH_3)_3 \)

1. **Identify the central atom**: The central atom is nitrogen (N).
2. **Count the valence electrons**: Nitrogen has 5 valence electrons.
3. **Count the bonds and lone pairs**:
- There are 3 \( SiH_3 \) groups attached to nitrogen, contributing 3 sigma bonds.
- There is 1 lone pair on nitrogen.
4. **Calculate the steric number**:
- Steric number = Number of sigma bonds + Number of lone pairs = 3 (bonds) + 1 (lone pair) = 4.
5. **Determine hybridization**:
- With a steric number of 4, the hybridization is \( sp^3 \).
6. **Determine the geometry**:
- The geometry is trigonal pyramidal due to the presence of the lone pair.

### Step 2: Analyze \( Me_3N \)

1. **Identify the central atom**: The central atom is nitrogen (N).
2. **Count the valence electrons**: Nitrogen has 5 valence electrons.
3. **Count the bonds and lone pairs**:
- There are 3 methyl (Me) groups attached to nitrogen, contributing 3 sigma bonds.
- There is 1 lone pair on nitrogen.
4. **Calculate the steric number**:
- Steric number = 3 (bonds) + 1 (lone pair) = 4.
5. **Determine hybridization**:
- With a steric number of 4, the hybridization is \( sp^3 \).
6. **Determine the geometry**:
- The geometry is also trigonal pyramidal due to the lone pair.

### Step 3: Analyze \( (SiH_3)_3P \)

1. **Identify the central atom**: The central atom is phosphorus (P).
2. **Count the valence electrons**: Phosphorus has 5 valence electrons.
3. **Count the bonds and lone pairs**:
- There are 3 \( SiH_3 \) groups attached to phosphorus, contributing 3 sigma bonds.
- There is 1 lone pair on phosphorus.
4. **Calculate the steric number**:
- Steric number = 3 (bonds) + 1 (lone pair) = 4.
5. **Determine hybridization**:
- With a steric number of 4, the hybridization is \( sp^3 \).
6. **Determine the geometry**:
- The geometry is trigonal pyramidal due to the lone pair.

### Summary of Geometries

- For \( N(SiH_3)_3 \): Trigonal pyramidal
- For \( Me_3N \): Trigonal pyramidal
- For \( (SiH_3)_3P \): Trigonal pyramidal