Question

The ion that is isoelectronic with CO is

• A. \( \text{O}_2^+ \)
• B. \( \text{CN}^- \)
• C. \( \text{O}_2^- \)
• D. \( \text{N}_2^+ \)

Hint:

To determine if two species are isoelectronic, compare their total number of electrons. Species with the same number of electrons are isoelectronic.

Answer 1

The Correct Option is B

Isoelectronic species have the same number of electrons. The electron configuration of \( \text{CO} \) is: - Carbon (C) has 6 electrons, and Oxygen (O) has 8 electrons.
- \( \text{CO} \) has a total of \( 6 + 8 = 14 \) electrons. Now, let's examine the options:
- \( \text{O}_2^+ \) has 15 electrons (Oxygen in \( \text{O}_2^+ \) loses one electron).
- \( \text{CN}^- \) has 14 electrons (Carbon has 6 electrons and Nitrogen has 7 electrons, plus the extra electron from the negative charge, making a total of 14 electrons).
- \( \text{O}_2^- \) has 17 electrons (Oxygen has 8 electrons per atom, plus an extra electron from the negative charge, totaling 17).
- \( \text{N}_2^+ \) has 13 electrons (Nitrogen has 7 electrons per atom, minus one due to the positive charge).
Thus, the ion that is isoelectronic with \( \text{CO} \) is \( \text{CN}^- \), which has 14 electrons.
Thus, the correct answer is \( \text{CN}^- \).