Chemistry S & P Block Elements SET 2019
PMDC Verified Question 72 of 104
In the third period of elements, there lies element "X" which is metallic in nature and it can reduce chlorine gas rapidly. To which group of elements does "X" belong?
A
IIA
B
VIIA
C
IVA
D
IA
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: IA
Concept:

The ability to rapidly reduce a non-metal (like Chlorine gas) implies the element is a very powerful reducing agent. The strongest reducing agents are metals with the lowest ionization energies.

Solution:

  • Reducing power is highest at the extreme left of the periodic table because these metals have large atomic radii and only 1 valence electron to lose.
  • Group I-A elements (Alkali metals, like Sodium in the 3rd period) have the lowest ionization energy in their respective periods.
  • Therefore, they vigorously and rapidly donate their electron to Chlorine, proving to be the strongest reducing agents. Element X must belong to Group I-A.


Why other options are incorrect:

  • Group II-A: Also strong reducers, but their higher IE makes them slower/less potent than Group I-A.
  • Groups IVA & VIIA: These are metalloids/non-metals that act predominantly as oxidizing agents, not reducing agents.

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