List of top Chemistry Questions on d And f - Block Elements

For which of the following ions will the magnetic moment ($\mu$) be maximum?

Explain with reasons:
(i) Transition metals show variable valency (variable oxidation states).
(ii) Copper is considered a transition metal even though it has a completely filled d-orbital \((3d^{10})\) in its \(+1\) state.

What is Lanthanide contraction? What are the consequences of Lanthanide contraction?

(i) Explain with reason that transition metals generally form coloured compounds.
(ii) Write a short note on the lanthanoid contraction.

Mention the different steps for the preparation of potassium permanganate from pyrolusite ore and draw the structure of permanganate ion. (1+1=2)

Which of the following ions has highest magnetic moment?

Compare the lanthanoid and actinoid elements with reference to the following: (i) Atomic and ionic sizes (ii) Oxidation state. (1½+1½=3)

Mention the different steps for the preparation of potassium dichromate from iron chromite ore and draw the structure of dichromate ion.

Which of the following ions forms coloured solution?

Explain, giving reasons:
i) Transition metals and most of their compounds are paramagnetic.
ii) Transition metals generally form coloured compounds.

Which of the following is a colourless ion?

Lanthanide contraction is observed in —

(i) Write the electronic configuration of the following ions: (a) Cr³⁺ (b) Cu²⁺.
(ii) Write the formula of chromate and dichromate ions.

What are the characteristics of transition metals? Why are they called transition metals?

The number of unpaired electrons in \( Cu^{2+} \) is

i) Write the electronic configuration of an element with atomic number 24.
ii) Find the number of unpaired electrons in the Co²⁺ ion.
iii) Why is the range of oxidation states in the actinoid series greater than in the lanthanoid series?

Why do the transition metals and many of their compounds act as catalysts? Explain.

For which of the following ions is the magnetic moment \( (\mu) \) the highest?

What is Lanthanoid contraction? Write in increasing order of basic nature of oxides \( (Ln_2O_3) \) and hydroxides \( [Ln(OH)_3] \) of Lanthanoids.

Transition metals, with a few exceptions, are extremely hard and less volatile. Explain.

Which of the following is not a transition metal?

Consider the metal complexes \( [Ni(en)_3]^{2+} \) (A), \( [NiCl_4]^{2-} \) (B) and \( [Ni(NH_3)_6]^{2+} \) (C). Choose the CORRECT option by considering the number of unpaired electrons present in (A), (B) and (C) respectively and the order of frequency of absorption.

The correct statements among the following are:
A. Mo(VI) and W(VI) are less stable than Cr(VI).
B. Ce⁴⁺ and Tb⁴⁺ are oxidant while Eu²⁺ and Yb²⁺ are reductant.
C. Cm and Am have seven unpaired electrons.
D. Actinoid contraction is greater from element to element than lanthanoid contraction.
Choose the correct answer:

The incorrect statement among the following is :

Choose the correct statements in respect of hydrides of group 15.
(A) Reducing power increases down the group
(B) Basic nature increases down the group
(C) Stability decreases down the group
(D) Boiling point decreases regularly down the group.