Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Metallic character decreases and non-metallic character increases on moving from left to right in a period.
Reason (R) : It is due to increase in ionisation enthalpy and decrease in electron gain enthalpy, when one moves from left to right in a period.
In the light of the above statements, choose the most appropriate answer from the options given below:
Assertion (A) : Metallic character decreases and non-metallic character increases on moving from left to right in a period.
Reason (R) : It is due to increase in ionisation enthalpy and decrease in electron gain enthalpy, when one moves from left to right in a period.
In the light of the above statements, choose the most appropriate answer from the options given below:
- (A)(A) is false but (R) is true.
- (B)Both (A) and (R) are correct and (R) is the correct explanation of (A)
- (C)Both (A) and (R) are correct but (R) is not the correct explanation of (A)
- (D)(A) is true but (R) is false✓ Correct
Answer: (D)
Solution
Across a period the nuclear charge increases and electrons are held more tightly, so metallic character falls and non-metallic character rises; the assertion is true. The reason fails where it says electron gain enthalpy decreases: from left to right the electron gain enthalpy becomes more negative, its magnitude growing together with the ionisation enthalpy. The assertion is true but the reason is false.
JEE Main · 2021 · 31 Aug 2021 · Shift 1 · Single correct option