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GS Paper IUPSC Prelims 2001
Health & Medicine
Question No. 303Interactive Test Mode
00:00
+2-0.66

Q303. In an atom, the order of filling up of the orbitals is governed by:

In an atom, the order of filling up of the orbitals is governed by:

Select the correct option below (or cross out options to eliminate)
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Official Answer Key & Detailed Solution

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Official UPSC Answer KeyUPSC Prelims 2001 • Science and Technology

Correct Answer: Option (A) — Aufbau’s principle

Concept & Option Breakdown

Standard Reference Verified
  • Aufbau's principle dictates that electrons fill subshells of lowest available energy before occupying higher energy levels, following the (n + l) rule.
  • Heisenberg's uncertainty principle states the fundamental limit on simultaneously knowing the position and momentum of a subatomic particle.
  • Hund's rule of maximum multiplicity governs electron pairing within degenerate orbitals.
  • Pauli's exclusion principle states that no two electrons in an atom can have the same set of four quantum numbers.
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Question Specifications & Syllabus Mapping

Examination & YearUPSC Civil Services Preliminary Examination 2001 (Q303)
Paper & Marking SchemeGS Paper I • 2 Marks (-0.66 Negative for incorrect response)
Syllabus Subject & TopicScience and Technology → Health & Medicine
Official Answer KeyOption (A) — Aufbau’s principle

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Frequently Asked Questions — UPSC Prelims 2001 Q303

What is the official answer for UPSC Prelims 2001 GS Paper I Question 303 (Science and Technology)?

The official UPSC answer key for this 2001 Science and Technology (Health & Medicine) question is Option (A): "Aufbau’s principle". Correct attempts carry 2 Marks with -0.66 Negative penalty for wrong answers.

Which UPSC Prelims syllabus topic does this 2001 question belong to?

This question belongs to GS Paper I under the subject "Science and Technology" and micro-topic "Health & Medicine". You can explore all repeated questions from Health & Medicine in Acme AI's 3D Prelims PYQ Realm or practice 50 full-length and sectional tests in the APT Prelims Test Series.

How can I solve this Health & Medicine UPSC Prelims question using option elimination?

To solve Health & Medicine questions in UPSC Prelims, identify extreme modifiers, verify core NCERT conceptual definitions, and eliminate mutually contradictory statement pairs before locking your final option.

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