The structure of `N(CH_(3))_(3)` is `"………….."` while that of `N(SiH_(3))_(3)` is `"………….."`.

Answer

To determine the structures of \( N(CH_3)_3 \) and \( N(SiH_3)_3 \), we will analyze each compound step by step.

### Step 1: Analyze the structure of \( N(CH_3)_3 \)

1. **Identify the central atom**: The central atom in \( N(CH_3)_3 \) is nitrogen (N).
2. **Count the bonds and lone pairs**: Nitrogen has one lone pair and forms three bonds with three methyl groups (CH₃).
3. **Determine hybridization**: The nitrogen atom undergoes sp³ hybridization because it has four regions of electron density (three bond pairs and one lone pair).
4. **Determine molecular geometry**: The presence of the lone pair results in a pyramidal shape (specifically, trigonal pyramidal) due to the repulsion between the lone pair and the bond pairs.
5. **Final structure**: The structure of \( N(CH_3)_3 \) is therefore trigonal pyramidal.

### Step 2: Analyze the structure of \( N(SiH_3)_3 \)

1. **Identify the central atom**: The central atom in \( N(SiH_3)_3 \) is again nitrogen (N).
2. **Count the bonds**: Nitrogen forms three bonds with three silane groups (SiH₃).
3. **Determine hybridization**: The bonding between nitrogen and silicon involves pπ-dπ back bonding due to the presence of d orbitals in silicon. This leads to sp² hybridization for nitrogen.
4. **Determine molecular geometry**: With three bond pairs and no lone pairs, the geometry is trigonal planar.
5. **Final structure**: The structure of \( N(SiH_3)_3 \) is therefore trigonal planar.

### Summary of Structures
- The structure of \( N(CH_3)_3 \) is **trigonal pyramidal**.
- The structure of \( N(SiH_3)_3 \) is **trigonal planar**.

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