Question

Which following pair of elements does NOT represent chemical twins?

• A. Nb - Ta
• B. Zr - Rf
• C. Mo - W
• D. Tc - Re

Hint:

Chemical twins are elements in the same group and period that exhibit similar properties.

Answer 1

The Correct Option is B

Step 1: Understanding chemical twins.
Chemical twins are pairs of elements where one element is a member of a transition series and the other is its homolog in the subsequent period. Zr and Rf are not chemical twins because they belong to different groups and periods.

Step 2: Analyzing the options.
(A) Nb - Ta: These elements are chemical twins as they belong to the same group in the periodic table and have similar chemical properties.
(B) Zr - Rf: Incorrect — Zr and Rf do not form a chemical twin pair. Zr is a transition metal, and Rf is a synthetic element.
(C) Mo - W: These are chemical twins, as they belong to the same group and have similar properties.
(D) Tc - Re: These are also chemical twins, belonging to the same group and exhibiting similar chemical behaviors.

Step 3: Conclusion.
The correct answer is (B) Zr - Rf, as they do not represent chemical twins.