Question

Which of the following sets contain atomic numbers of only representative elements? \[ \begin{aligned} \text{I.} \quad & 3,\;33,\;53,\;87 \\ \text{II.} \quad & 2,\;10,\;22,\;36 \\ \text{III.} \quad & 9,\;35,\;51,\;88 \\ \text{IV.} \quad & 17,\;25,\;37,\;48 \end{aligned} \] The correct answer is

• A. I \& II only
• B. II \& III only
• C. I \& III only
• D. II \& IV only \bigskip

Hint:

Representative elements include only: \begin{itemize} \item \(s\)-block (Groups 1 and 2) \item \(p\)-block (Groups 13--18) \end{itemize} They do \textbf{not} include transition (\(d\)-block) or inner transition (\(f\)-block) elements.

Answer 1

The Correct Option is C

Concept: Representative elements = s-block and p-block (Groups 1,2,13-18).

Step 1: Set I: 3(Li),33(As),53(I),87(Fr) → all representative. Set II: 22(Ti) is d-block → no. Set III: 9,35,51,88 → all representative. Set IV: 25(Mn),48(Cd) are d-block → no. I & III only.

Step 2: Write the final answer. \(\boxed{\text{I \& III only}}\)