✓ Board-verified
Chemistry · 2026 · 1 mark
CBSE 2026 · Region 1 · Set 3 · Q14
Assertion (A): Actinoids show irregularities in their electronic configurations. Reason (R): Due to varying stabilities of f^0, f^7 and f^14…
Assertion (A) : Actinoids show irregularities in their electronic configurations.
Reason (R) : Due to varying stabilities of $\displaystyle \mathrm{f}^{0}, \mathrm{f}^{7}$ and $\displaystyle \mathrm{f}^{14}$ occupancies of the 5f orbitals.
Official answer
(A)
Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
All The d-and f-Block Elements questions2026 question paperNCERT solutions: The d-and f-Block ElementsPractice The d-and f-Block Elements →
More from The d-and f-Block Elements
- Assertion: Transition metals show their highest oxidation state with oxygen. Reason (R): The ability of oxygen to form multiple bonds to metals.2023 · asked 2×
- Which of the following transition metals shows +1 and +2 oxidation states?2026 · asked 2×
- Assertion: Actinoids show wide range of oxidation states. Reason (R): Actinoids are radioactive in nature.2025 · asked 2×
- With increase in atomic number, the melting point of transition metals:2025
- In which of the following does the central atom exhibit an oxidation state of+3?2023
- (i) Silver atom has completely filled d-orbitals in its ground state, it is still considered to be a transition element. Justify the statement. (ii)…2022
- Give reasons for the following statements: Copper does not displace hydrogen from acids. Transition metals and most of their compounds show…2022
- Which one among the following metals of 3d series has the lowest melting point?2023
CBSE Class 12 Chemistry past-paper question from the 2026 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.