Which of the following species in neither hypervalent nor hypovalent ?

Options

A. `ClO_(4)^(-)`
B. `BF_(3)`
C. `SO_(4)^(2-)`
D. `CO_(3)^(2-)`

Explanation

To determine which of the given species is neither hypervalent nor hypovalent, we first need to understand the definitions of hypervalent and hypovalent species:

1. **Hypervalent Species**: These are species where the central atom has more than 8 electrons in its valence shell.
2. **Hypovalent Species**: These are species where the central atom has fewer than 8 electrons in its valence shell.

Now, let's analyze each of the provided options:

### Step 1: Analyze ClO4⁻ (Chlorate Ion)
- **Valence Electrons**: Chlorine (Cl) has 7 valence electrons, and each of the four oxygen (O) atoms contributes 6 valence electrons. The overall charge of -1 adds one more electron.
- Total = 7 (Cl) + 4×6 (O) + 1 (charge) = 7 + 24 + 1 = 32 valence electrons.
- In the Lewis structure, Cl is surrounded by 4 oxygen atoms, with double bonds to three of them and a single bond to one, resulting in 14 electrons around Cl.
- **Conclusion**: ClO4⁻ is hypervalent (14 > 8).

### Step 2: Analyze BF3 (Boron Trifluoride)
- **Valence Electrons**: Boron (B) has 3 valence electrons, and each of the three fluorine (F) atoms contributes 7 valence electrons.
- Total = 3 (B) + 3×7 (F) = 3 + 21 = 24 valence electrons.
- In the Lewis structure, B is surrounded by three F atoms, sharing 6 electrons total.
- **Conclusion**: BF3 is hypovalent (6 < 8).

### Step 3: Analyze SO4²⁻ (Sulfate Ion)
- **Valence Electrons**: Sulfur (S) has 6 valence electrons, and each of the four oxygen (O) atoms contributes 6 valence electrons. The overall charge of -2 adds two more electrons.
- Total = 6 (S) + 4×6 (O) + 2 (charge) = 6 + 24 + 2 = 32 valence electrons.
- In the Lewis structure, S is surrounded by four oxygen atoms, with double bonds to two of them and single bonds to the others, resulting in 12 electrons around S.
- **Conclusion**: SO4²⁻ is hypervalent (12 > 8).

### Step 4: Analyze CO3²⁻ (Carbonate Ion)
- **Valence Electrons**: Carbon (C) has 4 valence electrons, and each of the three oxygen (O) atoms contributes 6 valence electrons. The overall charge of -2 adds two more electrons.
- Total = 4 (C) + 3×6 (O) + 2 (charge) = 4 + 18 + 2 = 24 valence electrons.
- In the Lewis structure, C is surrounded by three oxygen atoms, with one double bond and two single bonds, resulting in 8 electrons around C.
- **Conclusion**: CO3²⁻ is neither hypervalent nor hypovalent (8 = 8).

### Final Answer:
The species that is neither hypervalent nor hypovalent is **CO3²⁻ (Carbonate Ion)**.