Chemistry Chemical Bonding NUMS 2023
PMDC Verified Question 34 of 102
The reason of highest electronegativity value of Fluorine is:
A
Complete outermost shell
B
Ability to form negative ion
C
Existence as diatomic molecule
D
Smaller size and higher nuclear change in the respective period
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: Smaller size and higher nuclear change in the respective period
Concept:

Electronegativity is driven by the nucleus's ability to attract shared electrons, which is maximized when the atom is small and the nuclear charge is high without excessive shielding.

Formula:

$$ \text{EN} \propto \frac{Z_{\text{eff}}}{\text{Atomic Radius}} $$

Solution:

  • Fluorine is at the far right of Period 2 (excluding the noble gas Neon).


  • It has a high effective nuclear charge (+9 protons pulling on just 2 electron shells).


  • Because it only has two shells, its atomic radius is extremely small, meaning the shared bonding electrons sit very close to the positive nucleus.


  • This combination of small size and high nuclear charge gives it the strongest pull on electrons (highest electronegativity).


Why other options are incorrect:

  • Option A: It does not have a complete outermost shell (it needs 1 more electron).
  • Option B & Option C: These are consequences of its chemistry, not the fundamental causes of its electronegativity.

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