Among the following group which represents the collection of isoelectronic species ?

Options

A. `NO, CN^(-), N_2, O_2^-`
B. `NO^+, C_2^(2-), O_2^(-) , CO`
C. `N_2, C_2^(2-) , CO, NO`
D. `CO, NO^(+), CN^(-), C_2^(2-)`

Explanation

To determine which group represents a collection of isoelectronic species, we need to calculate the total number of electrons in each species listed in the options. Isoelectronic species are those that have the same number of electrons. Let's analyze the groups step by step.

### Step 1: Identify the number of electrons in each species

1. **NO (Nitric Oxide)**
- Nitrogen (N) has 7 electrons.
- Oxygen (O) has 8 electrons.
- Total electrons in NO = 7 + 8 = 15 electrons.

2. **CN⁻ (Cyanide Ion)**
- Carbon (C) has 6 electrons.
- Nitrogen (N) has 7 electrons.
- The negative charge (-1) adds one more 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 (-1) removes one electron.
- Total electrons in NO⁺ = 7 + 8 - 1 = 14 electrons.

4. **C₂²⁻ (Dicarbon Ion)**
- Each Carbon (C) has 6 electrons, and there are 2 Carbons.
- The negative charge (-2) adds two more electrons.
- Total electrons in C₂²⁻ = (6 * 2) + 2 = 12 + 2 = 14 electrons.

5. **O₂²⁻ (Dioxygen Ion)**
- Each Oxygen (O) has 8 electrons, and there are 2 Oxygens.
- The negative charge (-2) adds two more electrons.
- Total electrons in O₂²⁻ = (8 * 2) + 2 = 16 + 2 = 18 electrons.

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

Now, let's summarize the total number of electrons calculated for each species:

- NO: 15 electrons
- CN⁻: 14 electrons
- NO⁺: 14 electrons
- C₂²⁻: 14 electrons
- O₂²⁻: 18 electrons

### Step 3: Identify the isoelectronic species

From the calculations, we can see that:
- CN⁻, NO⁺, and C₂²⁻ all have 14 electrons, making them isoelectronic species.
- NO has 15 electrons and O₂²⁻ has 18 electrons, so they do not belong to the same group.

### Conclusion

The group that represents the collection of isoelectronic species is CN⁻, NO⁺, and C₂²⁻.