Question

Among the following group which represents the collection of isoelectronic species?

• A. $NO,CN^ - ,N_2, O_2^ - $
• B. $NO^+ , C_2^{2-},O_2^- ,CO$
• C. $N_2,C_2^{2-} ,CO ,NO$
• D. $CO,NO^+ ,CN^- ,C_2^{2-}$

Answer 1

The Correct Option is D

 To determine which group represents the collection of isoelectronic species, we need to understand the concept of isoelectronic species. Isoelectronic species are atoms, molecules, or ions that have the same number of electrons.

Let's analyze each option:

1. \(NO, CN^-, N_2, O_2^-\)
   • NO: Nitric oxide has a total of 15 electrons (7 from N + 8 from O).
   • CN^-: 18 electrons (6 from C + 7 from N + 1 extra electron due to the negative charge).
   • N₂: 14 electrons (7 from each nitrogen atom).
   • O_2^-: 17 electrons (8 from each oxygen atom + 1 extra electron).
   • The number of electrons varies between these species, so they are not isoelectronic.
2. \(NO^+, C_2^{2-}, O_2^-, CO\)
   • NO⁺: 14 electrons (7 from N + 8 from O - 1 electron due to the positive charge).
   • C_2^2-: 14 electrons (6 from each C + 2 extra electrons due to the negative charge).
   • O_2^-: 17 electrons (8 from each O + 1 extra electron).
   • CO: 14 electrons (6 from C + 8 from O).
   • NO⁺, C_2^2-, and CO have 14 electrons, but O_2^- has 17. They are not all isoelectronic.
3. \(N_2, C_2^{2-}, CO, NO\)
   • N₂: 14 electrons.
   • C_2^2-: 14 electrons.
   • CO: 14 electrons.
   • NO: 15 electrons.
   • All except NO have 14 electrons, so they are not isoelectronic.
4. \(CO, NO^+, CN^-, C_2^{2-}\)
   • CO: 14 electrons.
   • NO⁺: 14 electrons.
   • CN^-: 14 electrons.
   • C_2^2-: 14 electrons.
   • All of these species have 14 electrons, making them isoelectronic.

Therefore, the correct answer is the group \(CO, NO^+, CN^-, C_2^{2-}\), as they all have the same number of electrons, making them isoelectronic.