Sum of `sigma and pi` bonds in `NH_(4)^(+)` cation is ..

Answer

To determine the sum of sigma and pi bonds in the NH4+ cation, we can follow these steps:

### Step 1: Identify the central atom and its valence electrons
- The central atom in NH4+ is nitrogen (N).
- Nitrogen has an atomic number of 7, which means it has 5 valence electrons.

### Step 2: Account for the positive charge
- The positive charge on the NH4+ cation indicates that nitrogen has lost one electron.
- Therefore, nitrogen effectively has 4 valence electrons available for bonding.

### Step 3: Determine the number of hydrogen atoms
- The NH4+ cation has 4 hydrogen (H) atoms surrounding the nitrogen.

### Step 4: Forming bonds
- Each hydrogen atom forms a single covalent bond with nitrogen by sharing one electron.
- Since nitrogen has 4 valence electrons and forms 4 bonds with 4 hydrogen atoms, it shares its 4 electrons.

### Step 5: Count the sigma and pi bonds
- In NH4+, all the bonds formed between nitrogen and hydrogen are single covalent bonds, which are classified as sigma (σ) bonds.
- There are no double or triple bonds present in NH4+, meaning there are no pi (π) bonds.

### Step 6: Calculate the total number of bonds
- Total sigma bonds = 4 (one for each N-H bond)
- Total pi bonds = 0 (no double or triple bonds)

### Final Answer
- The sum of sigma and pi bonds in NH4+ is:
\[ \text{Total bonds} = \text{Sigma bonds} + \text{Pi bonds} = 4 + 0 = 4 \]