Which of the following species is isoelectronic with CO?

Options

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

Explanation

To determine which species is isoelectronic with carbon monoxide (CO), we need to follow these steps:

### Step 1: Calculate the 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 given species to find the one with 14 electrons
We will check each option provided to see how many electrons each species has.

1. **HF (Hydrogen Fluoride)**
- Hydrogen (H) has 1 electron.
- Fluorine (F) has 9 electrons.
- Total electrons in HF = 1 + 9 = **10 electrons**.

2. **N2 (Nitrogen Gas)**
- Each nitrogen (N) atom has 7 electrons.
- Since there are 2 nitrogen atoms, total electrons in N2 = 7 + 7 = **14 electrons**.

3. **N2+ (Nitrogen Dimer with a Positive Charge)**
- N2 has 14 electrons (as calculated above).
- The positive charge indicates the loss of one electron.
- Total electrons in N2+ = 14 - 1 = **13 electrons**.

4. **O2- (Oxygen Dimer with a Negative Charge)**
- Each oxygen (O) atom has 8 electrons.
- Since there are 2 oxygen atoms, total electrons in O2 = 8 + 8 = 16 electrons.
- The negative charge indicates the gain of one electron.
- Total electrons in O2- = 16 + 1 = **17 electrons**.

### Step 3: Identify the isoelectronic species
From the calculations:
- HF has 10 electrons.
- N2 has 14 electrons.
- N2+ has 13 electrons.
- O2- has 17 electrons.

The only species that has the same number of electrons as CO (14 electrons) is **N2**.

### Final Answer:
The species that is isoelectronic with CO is **N2**.

---