The ion that is isoelectronic with CO is

Options

A. NO
B. `(O_2)^+`
C. `C_2`
D. `F_2`

Answer

To determine which ion is isoelectronic with carbon monoxide (CO), we first need to establish the number of electrons in CO.

### Step 1: Calculate 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: Identify ions or molecules that have 14 electrons.
We need to find species that also have a total of 14 electrons. Let's analyze some common species:

1. **NO (Nitric Oxide)**:
- Nitrogen (N) has 7 electrons.
- Oxygen (O) has 8 electrons.
- Total = 7 + 8 = 15 electrons (not isoelectronic).

2. **O2 (Oxygen Molecule)**:
- Each Oxygen (O) has 8 electrons.
- Total for O2 = 8 + 8 = 16 electrons (not isoelectronic).

3. **C (Carbon Atom)**:
- Carbon has 6 electrons.
- Total = 6 electrons (not isoelectronic).

4. **F2 (Fluorine Molecule)**:
- Each Fluorine (F) has 9 electrons.
- Total for F2 = 9 + 9 = 18 electrons (not isoelectronic).

5. **NO+ (Nitric Oxide Cation)**:
- NO has 15 electrons, but since it is a cation (NO+), it loses one electron.
- Total = 15 - 1 = 14 electrons (isoelectronic with CO).

### Conclusion:
The ion that is isoelectronic with CO is **NO+**.

### Final Answer:
**NO+**

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