The number of hypervalent species among the following
`ClO_(4)^(Theta),BF_(3),SO_(4)^(2-),CO_(3)^(2-)` is .

Explanation

To determine the number of hypervalent species among the given compounds \( \text{ClO}_4^- \), \( \text{BF}_3 \), \( \text{SO}_4^{2-} \), and \( \text{CO}_3^{2-} \), we need to analyze each species based on the definition of hypervalency. A hypervalent species is one in which the central atom has more than 8 electrons in its valence shell.

### Step-by-Step Solution:

1. **Identify the species**: The given species are \( \text{ClO}_4^- \), \( \text{BF}_3 \), \( \text{SO}_4^{2-} \), and \( \text{CO}_3^{2-} \).

2. **Analyze \( \text{ClO}_4^- \)**:
- Chlorine (Cl) is the central atom.
- In \( \text{ClO}_4^- \), chlorine forms four double bonds with oxygen.
- Each double bond contributes 2 electrons, so \( 4 \times 2 = 8 \) electrons from bonds.
- Additionally, there is a negative charge contributing 1 extra electron.
- Total electrons around Cl = \( 8 + 1 = 9 \) electrons.
- Since 9 > 8, \( \text{ClO}_4^- \) is hypervalent.

3. **Analyze \( \text{BF}_3 \)**:
- Boron (B) is the central atom.
- In \( \text{BF}_3 \), boron forms three single bonds with fluorine.
- Each bond contributes 2 electrons, so \( 3 \times 2 = 6 \) electrons.
- Total electrons around B = 6.
- Since 6 < 8, \( \text{BF}_3 \) is not hypervalent.

4. **Analyze \( \text{SO}_4^{2-} \)**:
- Sulfur (S) is the central atom.
- In \( \text{SO}_4^{2-} \), sulfur forms four double bonds with oxygen.
- Each double bond contributes 2 electrons, so \( 4 \times 2 = 8 \) electrons from bonds.
- Additionally, there are 2 extra electrons from the 2- charge.
- Total electrons around S = \( 8 + 2 = 10 \) electrons.
- Since 10 > 8, \( \text{SO}_4^{2-} \) is hypervalent.

5. **Analyze \( \text{CO}_3^{2-} \)**:
- Carbon (C) is the central atom.
- In \( \text{CO}_3^{2-} \), carbon forms one double bond with oxygen and two single bonds with two other oxygens.
- The double bond contributes 2 electrons and each single bond contributes 2 electrons, so total = \( 2 + 2 + 2 = 6 \) electrons.
- Additionally, there are 2 extra electrons from the 2- charge.
- Total electrons around C = \( 6 + 2 = 8 \) electrons.
- Since 8 = 8, \( \text{CO}_3^{2-} \) is not hypervalent.

6. **Count the hypervalent species**:
- The hypervalent species identified are \( \text{ClO}_4^- \) and \( \text{SO}_4^{2-} \).
- Therefore, there are **2 hypervalent species**.

### Final Answer:
The number of hypervalent species among the given compounds is **2**.