Chemistry Atomic Structure NUMS 2022
PMDC Verified Question 62 of 95
Apply \( (n+l) \) rule and calculate which of the following orbital has maximum energy?
A
\( 2d \)
B
\( 3s \)
C
\( 4s \)
D
\( 2p \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: \( 4s \)
Concept: The \( (n+l) \) rule dictates that orbitals with higher \( (n+l) \) sums exist at higher energy levels.

Formula: $$ \text{Energy} \propto (n+l) $$

Solution:
  • Let's calculate the values for the valid options:
  • \( 4s \): \( n=4, l=0 \implies n+l = 4 \)
  • \( 3s \): \( n=3, l=0 \implies n+l = 3 \)
  • \( 2p \): \( n=2, l=1 \implies n+l = 3 \)
  • Since \( 4s \) yields the highest sum (4), it represents the maximum energy among the valid choices.
  • Note: The \( 2d \) orbital is physically impossible because if \( n=2 \), \( l \) can only be 0 or 1.


Why other options are incorrect: Their \( (n+l) \) sums are lower, indicating they are filled earlier because they are lower in energy.

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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