Total number of species which used all three p-orbitals in hybridisation of central atom and should be non-polar also.
`XeO_(2)F_(2), SnCl_(2), IF_(5), I_(3)^(+), XeO_(4),SO_(2),XeF_(7)^(+),SeF_(4)`

Explanation

To solve the question of determining the total number of species that use all three p-orbitals in hybridization of the central atom and are also non-polar, we will analyze each given compound step by step.

### Step 1: Identify the compounds and their central atoms
The compounds given are:
1. XeO₂F₂
2. SnCl₂
3. IF₅
4. I₃⁺
5. XeO₄
6. SO₂
7. XeF₇⁺
8. SeF₄

### Step 2: Determine the hybridization and geometry of each compound
1. **XeO₂F₂**:
- Central atom: Xe
- Valence electrons = 8
- Bonds: 2 O and 2 F, 1 lone pair
- Steric number = 4 (2 bonds + 2 lone pairs)
- Hybridization = sp³
- Non-polar? No, because of the lone pair.

2. **SnCl₂**:
- Central atom: Sn
- Valence electrons = 4
- Bonds: 2 Cl, 1 lone pair
- Steric number = 3 (2 bonds + 1 lone pair)
- Hybridization = sp²
- Non-polar? No, because of the lone pair.

3. **IF₅**:
- Central atom: I
- Valence electrons = 7
- Bonds: 5 F, 1 lone pair
- Steric number = 6 (5 bonds + 1 lone pair)
- Hybridization = sp³d²
- Non-polar? No, because of the lone pair.

4. **I₃⁺**:
- Central atom: I
- Valence electrons = 7 (but +1 charge means 6 effective)
- Bonds: 2 I, 2 lone pairs
- Steric number = 4 (2 bonds + 2 lone pairs)
- Hybridization = sp³
- Non-polar? Yes, the geometry is linear and symmetrical.

5. **XeO₄**:
- Central atom: Xe
- Valence electrons = 8
- Bonds: 4 O, 0 lone pairs
- Steric number = 4 (4 bonds + 0 lone pairs)
- Hybridization = sp³
- Non-polar? Yes, symmetrical.

6. **SO₂**:
- Central atom: S
- Valence electrons = 6
- Bonds: 2 O, 1 lone pair
- Steric number = 3 (2 bonds + 1 lone pair)
- Hybridization = sp²
- Non-polar? No, because of the lone pair.

7. **XeF₇⁺**:
- Central atom: Xe
- Valence electrons = 8 (but +1 charge means 7 effective)
- Bonds: 7 F, 0 lone pairs
- Steric number = 7 (7 bonds + 0 lone pairs)
- Hybridization = sp³d³
- Non-polar? Yes, symmetrical.

8. **SeF₄**:
- Central atom: Se
- Valence electrons = 6
- Bonds: 4 F, 1 lone pair
- Steric number = 5 (4 bonds + 1 lone pair)
- Hybridization = sp³d
- Non-polar? No, because of the lone pair.

### Step 3: Summary of findings
- Non-polar species that use all three p-orbitals:
- I₃⁺ (sp³ hybridization)
- XeO₄ (sp³ hybridization)
- XeF₇⁺ (sp³d³ hybridization)

### Conclusion
The total number of species that use all three p-orbitals in hybridization of the central atom and are non-polar is **3**.