Question

The ion which is isoelectronic with CO is

• A. $CN^-$
• B. $O^-_2$
• C. $N^+_2$
• D. $O^+_2$

Hint:

An ion is an atom or a molecule which has a net electric charge. The charge on the atom can be either positive or negative.

Answer 1

The Correct Option is A

The correct option is(A): \(CN^-\)
An ion refers to an electronically charged atom or molecule or any species other than the neutral charge. Ion can either be positively or negatively charged. The positive charged ions are called as cation and the negative charged ions are termed as anion.
The cation is formed by the loss of electrons and the anion is formed by gain of electrons. The cation is labeled as X⁺ and an anion is labeled as Y^- ion.
The term isoelectronic is related to the number of electrons present on the respective atom or ion. Isoelectronic species are the having same number of electrons. The number of electrons can be calculated as mentioned below:
Number of electrons in CO = 6 + 8 = 14 
Number of electrons in \(O_2^-\) = 16 + 1 = 17 
Number of electrons in \(N_2^+\) = 14 - 1 = 13 
Number of electrons in \(O_2^+\) = 1 6 - 1 = 15 
Number of electrons in \(CN^-\) = 6 + 7 + 1 = 14 
Hence, CO isoelectronic with \(CN^-\) ion.

Answer 2

"Ion" is a term used to describe a species that has a charge other than neutral. This charge can either be positive or negative. When an ion has a positive charge, it is called a cation; when it has a negative charge, it is called an anion. A cation is created when an atom loses electrons, while an anion is formed when an atom gains electrons. Cations are identified as X⁺ and anions as Y⁻ ions. The term "isoelectronic" pertains to atoms, ions, or molecules with the same electronic structure and the same number of valence electrons. The prefix "iso" means the same, while "electronic" means electrons. Isoelectronic species share similar chemical properties. 

The number of electrons for each atoms or ions is calculated as follows:

For CO : number of electrons of C⁺ number of electrons of O = 6+8=14electrons 

For O₂⁻ : 2 × number of electrons of O + 1 = 2×8+1=17electrons

For N₂⁺ : 2 × number of electrons of N - 1 = 2×7−1=13elecrtons. 

For CN⁻ : number of electrons of C + number of electrons of N + 1 = 6+7+1=14electrons. 

For O₂⁺ : 2 × number of electrons of O – 1 = 2×8−1=15electrons. Of the given four ions the CN⁻ ion has 14 electrons which are the same with the CO.

Hence, A is the correct option