The geometry with respect to 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

Explanation

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 follow these steps:

### 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. **Determine the number of bonds**: There are 3 \( SiH_3 \) groups attached, contributing 3 bond pairs.
4. **Count lone pairs**: Since nitrogen has 5 valence electrons and is forming 3 bonds, it has \( 5 - 3 = 2 \) lone pairs.
5. **Calculate the steric number**: The steric number is the sum of bond pairs and lone pairs: \( 3 \text{ (bond pairs)} + 2 \text{ (lone pairs)} = 5 \).
6. **Determine hybridization**: A steric number of 5 corresponds to \( sp^3d \) hybridization.
7. **Predict geometry**: With \( sp^3d \) hybridization and 2 lone pairs, the geometry is trigonal bipyramidal with a bent shape due to the lone pairs.

### 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. **Determine the number of bonds**: There are 3 methyl (Me) groups attached, contributing 3 bond pairs.
4. **Count lone pairs**: Since nitrogen has 5 valence electrons and is forming 3 bonds, it has \( 5 - 3 = 2 \) lone pairs.
5. **Calculate the steric number**: The steric number is \( 3 \text{ (bond pairs)} + 1 \text{ (lone pair)} = 4 \).
6. **Determine hybridization**: A steric number of 4 corresponds to \( sp^3 \) hybridization.
7. **Predict geometry**: With \( sp^3 \) hybridization and 1 lone pair, the geometry is trigonal pyramidal.

### 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. **Determine the number of bonds**: There are 3 \( SiH_3 \) groups attached, contributing 3 bond pairs.
4. **Count lone pairs**: Since phosphorus has 5 valence electrons and is forming 3 bonds, it has \( 5 - 3 = 2 \) lone pairs.
5. **Calculate the steric number**: The steric number is \( 3 \text{ (bond pairs)} + 1 \text{ (lone pair)} = 4 \).
6. **Determine hybridization**: A steric number of 4 corresponds to \( sp^3 \) hybridization.
7. **Predict geometry**: With \( sp^3 \) hybridization and 1 lone pair, the geometry is trigonal pyramidal.

### Summary of Geometries
- \( N(SiH_3)_3 \): Trigonal bipyramidal (bent)
- \( Me_3N \): Trigonal pyramidal
- \( (SiH_3)_3P \): Trigonal pyramidal