Concept: This is a historically flawed past paper question. The options provided do not contain the correct formula for the maximum number of
electrons in a subshell, but the answer key selects the formula for the number of
orbitals.
Formula: $$ \text{Electrons} = 2(2l+1) $$ $$ \text{Orbitals} = 2l+1 $$
Solution: - The true maximum number of electrons in a subshell is calculated by \( 2(2l+1) \).
- None of the given options perfectly represent this.
- However, Option D, \( 2l+1 \), calculates the number of spatial orientations (orbitals) within a subshell.
- In the context of this specific exam's flawed answer key, \( 2l+1 \) is designated as the 'correct' option, likely due to a typographic error by the examiners omitting the multiplier of 2.
Why other options are incorrect: \( n^2 \) is the number of orbitals in a shell. \( 2n^2 \) is the maximum number of electrons in an entire principal shell. \( 2(n+1) \) has no specific quantum meaning.
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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.