Ionisation enthalpies of early actinoids are lower than early lanthanoids. This is because 5f orbitals will penetrate less into the inner core of electrons. The 5f electrons, will be more effectively shielded from the nuclear charge than the 4f electrons of corresponding lanthanoids.
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Ionisation enthalpies of…
NEET UG 2023 — Chemistry Inorganic Chemistry
2023mcqmedium
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Ionisation enthalpies of early actinoids are lower than for early lanthanoids. Reason (R) : Electrons are entering 5f orbitals in actinoids which experience greater shielding from nuclear charge. In the light of the above statements, choose the correct answer from the options given below:
Official previous-year question
Held on 30 Apr 2023 · Verified 9 Jul 2026.
Options
- A
Both (A) and (R) are true and (R) is the correct explanation of (A).
- B
Both (A) and (R) are true but (R) is not the correct explanation of (A).
- C
(A) is true but (R) is false.
- D
(A) is false but (R) is true.
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