Chemistry Chemical Bonding DUHS 2022
PMDC Verified Question 50 of 102
Cation & anion formed which combines to form crystal lattices:
A
Only cations is isoelectronic to nearest noble gas
B
Cation & anion both are isoelectronic to nearest noble gas
C
Cation & anion both are isoelectronic to nearest noble gas & No of electron lost by metal & No of electrons gained by nonmetal are equal
D
Only anion is isoelectronic by nearest noble gas
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: Cation & anion both are isoelectronic to nearest noble gas
Concept:

Ionic bonds form so that both participating atoms can achieve a stable, lower-energy electron configuration, typically an octet.

Formula:

$$ \text{Na} \rightarrow \text{Na}^+ \ ([\text{Ne}]) \quad ; \quad \text{Cl} + e^- \rightarrow \text{Cl}^- \ ([\text{Ar}]) $$

Solution:

  • Metals lose electrons to empty their valence shell, exposing the full stable shell beneath (becoming isoelectronic with the preceding noble gas).


  • Nonmetals gain electrons to completely fill their current valence shell (becoming isoelectronic with the succeeding noble gas).


  • Thus, in stable ionic crystal lattices, both the resulting cations and anions achieve a stable noble gas configuration.


Why other options are incorrect:

  • Option A & Option D: It is not an exclusive process; both ions achieve stability simultaneously.
  • Option C: While true that total electrons lost equals total gained in the bulk compound, option B is the fundamental driving force for the individual ions' stability as per standard textbook phrasing.

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