Explain actinoid contraction .

Statement-1 : Lanthanoid contraction is more important than actinoid contraction is more important than actinoid contraction. Statement-2 : Chemistry of elements surrounding the actinoids are much less known at the present time.

Assign reasons for the following : (i) Cu(I) ion is not known to exist in aqueous solutions. (ii) Transition metals are much harder than the alkali metals. (iii) From element to element actinoid contraction is greater than the lanthanoid contraction.

Zr and Hf have almost equal atomic and ionic radii because of (a) lanthanoid contraction (b) diagonal relationship (c) actinoid contraction (d) belonging to the same group

Does actinoids show actinoid contraction similar to lanthanoid contraction ?

Why actinoid contraction is more than lanthanoid contraction

(i) Give the general electronic configuration of d-block elements, (ii) Silver atom has completely filled d-orbitals (4d^10) in its ground state. Yet, it is considered as transition element. Why? (iii) Cu^+ ion is not stable in aqueous solution. Explain. (iv) Actinoids contraction is greater from element to element than lanthanoid contraction. Why?