The number of `90^(@)` bond angles present in `SF_(4)` molecules is

Explanation

To determine the number of `90°` bond angles present in the `SF₄` molecule, we need to analyze its molecular structure and hybridization.

### Step-by-Step Solution:

1. **Identify the Valence Electrons:**
- Sulfur (S) has an atomic number of 16. The electronic configuration is `1s² 2s² 2p⁶ 3s² 3p⁴`.
- The valence electrons for sulfur are in the 3s and 3p orbitals. Sulfur has 6 valence electrons (2 from 3s and 4 from 3p).

2. **Determine the Hybridization:**
- The formula for hybridization is given by:
\[ \text{Hybridization} = \frac{1}{2} \left( \text{Valence Electrons} + \text{Monovalent Atoms} \right) \]
- For `SF₄`, there are 4 fluorine atoms (which are monovalent).
- Thus, the calculation is:
\[ \text{Hybridization} = \frac{1}{2} \left( 6 + 4 \right) = \frac{10}{2} = 5 \]
- This indicates that the hybridization of sulfur in `SF₄` is `sp³d`.

3. **Analyze the Molecular Geometry:**
- The `sp³d` hybridization corresponds to a trigonal bipyramidal geometry.
- In this geometry, there are 5 positions: 3 equatorial and 2 axial.

4. **Identify Lone Pairs and Bond Pairs:**
- In `SF₄`, there are 4 bond pairs (from the 4 fluorine atoms) and 1 lone pair on sulfur.
- The presence of the lone pair affects the geometry, leading to a seesaw shape.

5. **Determine Bond Angles:**
- In a seesaw geometry, the bond angles are not all equal.
- The equatorial bond angles are approximately `120°`, and the axial-equatorial bond angles are less than `90°` due to the lone pair's repulsion.

6. **Count the `90°` Bond Angles:**
- In the seesaw structure of `SF₄`, there are no `90°` bond angles present. The angles between the axial and equatorial bonds are less than `90°` due to the lone pair's influence.

### Conclusion:
The number of `90°` bond angles present in `SF₄` is **0**.