COMPASSLearning
RegisterLogin

CBSE Class 12 · 2000 · Delhi Compartment · d and f Block ElementsVery Short Answer

WhatsApp Email
State the common characteristic of actinoids and lanthanoids which places them in the f-block of elements.

Answer: In both, the differentiating (last) electron enters the (n−2)f subshell — 4f for lanthanoids, 5f for actinoids.

Solution

In both series the last electron enters an f-orbital of the antepenultimate shell, (n−2)f:

(4f for the lanthanoids, 5f for the actinoids) — this filling of f-orbitals places them in the f-block.

CBSE Class 12 Board · 2000 · Delhi Compartment · Subjective

Practise more: all CBSE board PYQs on d and f Block Elements →

More board questions on d and f Block Elements

  1. Transition metals are known to form interstitial compounds. The formation of interstitial compounds makes the transition metal:
    CBSE 2024View solution →
  2. Assertion (A): Zr and Hf have almost similar atomic radii.
    Reason (R): This is due to lanthanoid contraction.
    CBSE 2024View solution →
  3. Which of the following ions has the electronic configuration 3d? (Atomic numbers: Mn = 25, Co = 27, Ni = 28)
    CBSE 2023View solution →
  4. Which property of transition metals enables them to behave as catalysts?
    CBSE 2023View solution →
  5. (a) A transition element X has the electronic configuration [Ar]4s²3d³. Predict its likely oxidation states.
    CBSE 2023View solution →
  6. a) Write any two consequences of lanthanoid contraction.
    b) Name the element of the 3d series which exhibits the largest number of oxidation states. Give a reason.
    CBSE 2022View solution →