The ion that is iso - electronic with CO is

Options

A. `CN^(-)`
B. `O_(2)^(+)`
C. `O_(2)^(-)`
D. `N_(2)^(+)`

Explanation

To determine the ion that is iso-electronic with carbon monoxide (CO), we need to follow these steps:

### Step 1: Determine the total number of electrons in CO
- Carbon (C) has 6 electrons.
- Oxygen (O) has 8 electrons.
- Therefore, the total number of electrons in CO = 6 (from C) + 8 (from O) = 14 electrons.

### Step 2: Analyze the options to find an ion with 14 electrons
We need to check each option provided to see which one has a total of 14 electrons.

#### Option A: CN⁻ (Cyanide ion)
- Carbon (C) has 6 electrons.
- Nitrogen (N) has 7 electrons.
- The negative charge indicates that it has gained 1 extra electron.
- Total electrons = 6 (from C) + 7 (from N) + 1 (extra electron) = 14 electrons.

#### Option B: O₂⁺ (Oxygen dication)
- Each oxygen (O) has 8 electrons.
- There are 2 oxygen atoms, so total = 2 × 8 = 16 electrons.
- The positive charge indicates that it has lost 1 electron.
- Total electrons = 16 - 1 = 15 electrons.

#### Option C: O₂⁻ (Oxygen anion)
- Each oxygen (O) has 8 electrons.
- There are 2 oxygen atoms, so total = 2 × 8 = 16 electrons.
- The negative charge indicates that it has gained 1 extra electron.
- Total electrons = 16 + 1 = 17 electrons.

#### Option D: N₂⁺ (Nitrogen dication)
- Each nitrogen (N) has 7 electrons.
- There are 2 nitrogen atoms, so total = 2 × 7 = 14 electrons.
- The positive charge indicates that it has lost 1 electron.
- Total electrons = 14 - 1 = 13 electrons.

### Step 3: Conclusion
From the analysis, only CN⁻ has a total of 14 electrons, which makes it iso-electronic with CO. Therefore, the answer is:

**The ion that is iso-electronic with CO is CN⁻.**