Chemistry S & P Block Elements MDCAT 2018
PMDC Verified Question 81 of 104
In period 2 and period 3 maximum melting point shown by elements
A
Lithium and sodium
B
Carbon and silicon
C
Neon and argon
D
Nitrogen and phosphorous
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: Carbon and silicon
Concept:

Maximum melting points in any short period are observed for elements that can form giant three-dimensional covalent network lattices.

Solution:

  • In Period 2, Carbon (Group IVA) forms massive covalent structures like diamond, giving it the highest melting point.
  • In Period 3, Silicon (Group IVA) also forms a similar giant covalent network, requiring enormous energy to break its bonds.
  • Therefore, Carbon and Silicon exhibit the maximum melting points in their respective periods.


Why other options are incorrect:

  • Option A: Alkali metals have relatively weak metallic bonds and low melting points.
  • Option C: Noble gases exist as monoatomic gases with very weak London dispersion forces.
  • Option D: Nitrogen and phosphorus form discrete molecules (\( \text{N}_2 \), \( \text{P}_4 \)) with weak intermolecular forces.

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