Which of the following are iso-electronic as well as iso-structural ?
`NO_(3)^(-),CO_(3)^(2-),ClO_(3)^(-),SO_(3)`

Options

A. All have linear shape.
B. All have trigonal planar shape.
C. All have tetrahedral shape.
D. All have trigonal pyramidal shape.

Explanation

To determine which of the given species are isoelectronic and isostructural, we will follow these steps:

### Step 1: Calculate the total number of electrons for each species.

1. **For NO₃⁻ (Nitrate ion)**:
- Nitrogen (N) has 7 electrons.
- Each Oxygen (O) has 8 electrons, and there are 3 Oxygens: 3 × 8 = 24 electrons.
- The negative charge adds 1 electron.
- Total = 7 + 24 + 1 = **32 electrons**.

2. **For CO₃²⁻ (Carbonate ion)**:
- Carbon (C) has 6 electrons.
- Each Oxygen (O) has 8 electrons, and there are 3 Oxygens: 3 × 8 = 24 electrons.
- The double negative charge adds 2 electrons.
- Total = 6 + 24 + 2 = **32 electrons**.

3. **For ClO₃⁻ (Chlorate ion)**:
- Chlorine (Cl) has 17 electrons.
- Each Oxygen (O) has 8 electrons, and there are 3 Oxygens: 3 × 8 = 24 electrons.
- The negative charge adds 1 electron.
- Total = 17 + 24 + 1 = **42 electrons**.

4. **For SO₃ (Sulfur trioxide)**:
- Sulfur (S) has 16 electrons.
- Each Oxygen (O) has 8 electrons, and there are 3 Oxygens: 3 × 8 = 24 electrons.
- There is no charge to add.
- Total = 16 + 24 = **40 electrons**.

### Step 2: Identify which species are isoelectronic.

From the calculations:
- NO₃⁻ has 32 electrons.
- CO₃²⁻ has 32 electrons.
- ClO₃⁻ has 42 electrons.
- SO₃ has 40 electrons.

**Conclusion**: NO₃⁻ and CO₃²⁻ are isoelectronic since they both have 32 electrons.

### Step 3: Determine the molecular structure of the isoelectronic species.

1. **Structure of NO₃⁻ (Nitrate ion)**:
- The structure is trigonal planar with nitrogen in the center, one double bond with oxygen, and two single bonds with the other two oxygens.

2. **Structure of CO₃²⁻ (Carbonate ion)**:
- The structure is also trigonal planar with carbon in the center, one double bond with oxygen, and two single bonds with the other two oxygens.

### Step 4: Check if they are isostructural.

Both NO₃⁻ and CO₃²⁻ have the same trigonal planar structure.

### Final Answer:
The species that are both isoelectronic and isostructural are **NO₃⁻ and CO₃²⁻**.

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