Chemistry Transition Elements PMDC 2024
PMDC Verified Question 4 of 68
What is the range of atomic numbers of the 3d series of transition elements? [Practice Question]
A
20-30
B
22-30
C
21-30
D
24-30
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: 21-30
Concept:

The \(3d\) transition series (first transition series) is located in the fourth period of the periodic table, following Calcium.

Solution:

  • Calcium has an atomic number of 20 (ends in \(4s^2\)).


  • The filling of the \(3d\) subshell begins with the very next element, Scandium (Sc), which has an atomic number of 21.


  • The series continues across the block as the \(3d\) subshell fills, ending with Zinc (Zn), which has a completely filled \(3d^{10}\) subshell and an atomic number of 30.


  • Therefore, the range is strictly 21 to 30.


Why other options are incorrect:

  • 20: This is Calcium, an alkaline earth metal (s-block).


  • 22: This is Titanium; starting here would exclude Scandium.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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