JEE Mains · Chemistry · STD 11 - 2. structure of atom

Which one of the following sets of ions represents a collection of isoelectronic species? (Given : Atomic Number: F :9, \(Cl : 17, Na =11\), \(Mg =12, Al =13, K =19, Ca =20, Sc =21\) )

A \(Ci ^{+}, Na ^{+}, Mg ^{2+}, Ca ^{2+}\)
B \(\left. Ba ^{2+}, Sr ^{2+}, K +, Ca ^{2+}\right.\)
C \(\left. N ^{3-}, O ^{2-}, F , S ^{2-}\right.\)
D \(\left. K ^{+}, Cl ^{-}, Ca ^{2+}, Sc ^{3+}\right.\)

Verified Solution

Answer & Solution

Correct Answer

(D) \(\left. K ^{+}, Cl ^{-}, Ca ^{2+}, Sc ^{3+}\right.\)

Step-by-step Solution

Detailed explanation

\(K ^{+} Cl ^1 Ca ^{2+} Sc ^{3+}\) \(\begin{array}{llll}18 & 18 & 18 & 18\end{array}\)

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

Same subject

Match the LIST-I with LIST-II

List-I Amino acid	List-II Positive reaction/Test for functional group present in side chain of amino acid
A. Glutamine	I. Hinsberg's test
B. Lysine	II. Neutral \(\text{FeCl}_3\) test
C. Tyrosine	III. Ceric ammonium nitrate test
D. Serine	IV. Hoffman bromamide degradation

Choose the correct answer from the options given below:

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