Of the following sets which one does NOT contain isoelectronic species?

Structure of Atom PYQ — JEE Main 2005 · Shift 0 · Q55 with Solution

View written solutionFree

Correct answer: B

Idea of isoelectronic species

Species are isoelectronic if they have the same total number of electrons.
Check each option by counting total electrons

Option A: $BO_3^{3-}$ , $CO_3^{2-}$ , $NO_3^{-}$

For $BO_3^{3-}$ : $Z_B + 3Z_O + 3 = 5 + 3(8) + 3 = 5 + 24 + 3 = 32$
For $CO_3^{2-}$ : $Z_C + 3Z_O + 2 = 6 + 24 + 2 = 32$
For $NO_3^{-}$ : $Z_N + 3Z_O + 1 = 7 + 24 + 1 = 32$

All have $32$ electrons, so these are isoelectronic.

Option B: $SO_3^{2-}$ , $CO_3^{2-}$ , $NO_3^{-}$

For $SO_3^{2-}$ : $Z_S + 3Z_O + 2 = 16 + 24 + 2 = 42$
For $CO_3^{2-}$ : $6 + 24 + 2 = 32$
For $NO_3^{-}$ : $7 + 24 + 1 = 32$

Here, $SO_3^{2-}$ has $42$ electrons, while the other two have $32$ electrons. So this set is not isoelectronic.

Option C: $CN^{-}$ , $N_2$ , $C_2^{2-}$

For $CN^{-}$ : $6 + 7 + 1 = 14$
For $N_2$ : $7 + 7 = 14$
For $C_2^{2-}$ : $2(6) + 2 = 14$

All have $14$ electrons, so these are isoelectronic.

Option D: $PO_4^{3-}$ , $SO_4^{2-}$ , $ClO_4^{-}$

For $PO_4^{3-}$ : $15 + 4(8) + 3 = 15 + 32 + 3 = 50$
For $SO_4^{2-}$ : $16 + 32 + 2 = 50$
For $ClO_4^{-}$ : $17 + 32 + 1 = 50$

All have $50$ electrons, so these are isoelectronic.

Conclusion

The set which does not contain isoelectronic species is: $\boxed{B}$

Comparison with stored correct answer

Stored correct answer: $B$

My derived answer also is $B$ , so they agree.

Structure of Atom question

Structure of Atom question

Option A: $BO_3^{3-}$ , $CO_3^{2-}$ , $NO_3^{-}$

Option B: $SO_3^{2-}$ , $CO_3^{2-}$ , $NO_3^{-}$

Option C: $CN^{-}$ , $N_2$ , $C_2^{2-}$

Option D: $PO_4^{3-}$ , $SO_4^{2-}$ , $ClO_4^{-}$

More from Structure of Atom

Structure of Atom question

Structure of Atom question

Option A: $BO_3^{3-}$ , $CO_3^{2-}$ , $NO_3^{-}$

Option B: $SO_3^{2-}$ , $CO_3^{2-}$ , $NO_3^{-}$

Option C: $CN^{-}$ , $N_2$ , $C_2^{2-}$

Option D: $PO_4^{3-}$ , $SO_4^{2-}$ , $ClO_4^{-}$

More from Structure of Atom

Option A: BO33−BO_3^{3-}BO33−​, CO32−CO_3^{2-}CO32−​, NO3−NO_3^{-}NO3−​

Option B: SO32−SO_3^{2-}SO32−​, CO32−CO_3^{2-}CO32−​, NO3−NO_3^{-}NO3−​

Option C: CN−CN^{-}CN−, N2N_2N2​, C22−C_2^{2-}C22−​

Option D: PO43−PO_4^{3-}PO43−​, SO42−SO_4^{2-}SO42−​, ClO4−ClO_4^{-}ClO4−​

More from Structure of Atom

Option A: BO33−BO_3^{3-}BO33−​, CO32−CO_3^{2-}CO32−​, NO3−NO_3^{-}NO3−​

Option B: SO32−SO_3^{2-}SO32−​, CO32−CO_3^{2-}CO32−​, NO3−NO_3^{-}NO3−​

Option C: CN−CN^{-}CN−, N2N_2N2​, C22−C_2^{2-}C22−​

Option D: PO43−PO_4^{3-}PO43−​, SO42−SO_4^{2-}SO42−​, ClO4−ClO_4^{-}ClO4−​

More from Structure of Atom

Option A: $BO_3^{3-}$ , $CO_3^{2-}$ , $NO_3^{-}$

Option B: $SO_3^{2-}$ , $CO_3^{2-}$ , $NO_3^{-}$

Option C: $CN^{-}$ , $N_2$ , $C_2^{2-}$

Option D: $PO_4^{3-}$ , $SO_4^{2-}$ , $ClO_4^{-}$

Option A: $BO_3^{3-}$ , $CO_3^{2-}$ , $NO_3^{-}$

Option B: $SO_3^{2-}$ , $CO_3^{2-}$ , $NO_3^{-}$

Option C: $CN^{-}$ , $N_2$ , $C_2^{2-}$

Option D: $PO_4^{3-}$ , $SO_4^{2-}$ , $ClO_4^{-}$