Isoelectronic species are

Options

A. `CO, CN^(-) , NO^(+) ,C_(2)^(2-)`
B. `CO^(-) ,CN,NO,C_(2)^(-)`
C. `CO^(+) ,CN^(+),NO^(-) ,C_(2)`
D. `CO,CN,NO,C_(2)`

Answer

To determine the isoelectronic species among the given options, we need to find the total number of electrons in each species. Isoelectronic species are those that have the same number of electrons. Let's analyze each option step by step.

### Step 1: Identify the species and calculate the total number of electrons.

1. **CO (Carbon Monoxide)**
- Carbon (C) has 6 electrons.
- Oxygen (O) has 8 electrons.
- Total electrons in CO = 6 + 8 = 14 electrons.

2. **CN⁻ (Cyanide Ion)**
- Carbon (C) has 6 electrons.
- Nitrogen (N) has 7 electrons.
- The negative charge (⁻) indicates 1 extra electron.
- Total electrons in CN⁻ = 6 + 7 + 1 = 14 electrons.

3. **NO⁺ (Nitric Oxide Cation)**
- Nitrogen (N) has 7 electrons.
- Oxygen (O) has 8 electrons.
- The positive charge (⁺) indicates 1 less electron.
- Total electrons in NO⁺ = 7 + 8 - 1 = 14 electrons.

4. **C₂²⁻ (Dicarbon Ion)**
- Each Carbon (C) has 6 electrons, and there are 2 carbon atoms.
- The double negative charge (²⁻) indicates 2 extra electrons.
- Total electrons in C₂²⁻ = (6 + 6) + 2 = 14 electrons.

### Step 2: Compare the total number of electrons.

- CO: 14 electrons
- CN⁻: 14 electrons
- NO⁺: 14 electrons
- C₂²⁻: 14 electrons

### Conclusion:

All four species (CO, CN⁻, NO⁺, C₂²⁻) have the same number of electrons (14). Therefore, they are all isoelectronic species.

### Final Answer:
The isoelectronic species are CO, CN⁻, NO⁺, and C₂²⁻.

---