Chemistry Atomic Structure PMC 2021
PMDC Verified Question 67 of 95
M-shell contain:
A
\( s \)
B
\( s, p, d \)
C
\( s, p \)
D
\( s, p, d, f \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: \( s, p, d \)
Concept: The principal quantum number \(n\) determines the number of subshells within that shell.

Formula: $$ \text{Number of subshells} = n $$

Solution:
  • The shells are lettered K, L, M, N... corresponding to \( n = 1, 2, 3, 4\dots \)
  • For the M-shell, \( n = 3 \).
  • An energy level \(n\) contains exactly \(n\) subshells.
  • Therefore, the M-shell has 3 subshells: \(s\) (\(l=0\)), \(p\) (\(l=1\)), and \(d\) (\(l=2\)).


Why other options are incorrect: Option A describes the K-shell. Option C describes the L-shell. Option D describes the N-shell.

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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