Chemistry S & P Block Elements UHS 2023
PMDC Verified Question 27 of 104
The electronic configurations of some elements are given below. Recognize the element that belongs to group IIIA
A
\( 1s^2 2s^2 2p^3 \)
B
\( 1s^2 2s^2 2p^4 \)
C
\( 1s^2 2s^2 2p^1 \)
D
\( 1s^2 2s^2 2p^2 \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: \( 1s^2 2s^2 2p^1 \)
Concept:

The group number in the A-group classification corresponds exactly to the total number of valence electrons (electrons in the outermost 's' and 'p' orbitals).

Solution:

  • Group IIIA elements must have exactly 3 valence electrons in their outermost shell.
  • Let's examine the valence shell (the outermost principle shell, \( n=2 \)) of each option:
    A. \( 2s^2 2p^3 \) -> 2 + 3 = 5 valence electrons (Group VA).
    B. \( 2s^2 2p^4 \) -> 2 + 4 = 6 valence electrons (Group VIA).
    C. \( 2s^2 2p^1 \) -> 2 + 1 = 3 valence electrons (Group IIIA).
    D. \( 2s^2 2p^2 \) -> 2 + 2 = 4 valence electrons (Group IVA).
  • Option C matches the required 3 valence electrons for Group IIIA (specifically, this is the configuration for Boron).


Why other options are incorrect:

  • They have incorrect numbers of valence electrons for Group IIIA.

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.

Previous Question All S & P Block Elements MCQs Next Question

Want to solve full-length papers under timed exam conditions?

Practice with zero-scroll lockdown sprints, dynamic latency zone timers, live peer selection telemetry, and the automated Amber mistake recovery loop.

Enter Arena Sprint iOS App Android App