COMPARISON OF LANTHANOIDS & ACTINOIDS

Compounds OF d block element FeSO4.7H2O||CuSO4.5H2O||AgNO3|| Properties OF Lanthanoids and Actinoids

Comparison OF polarising OF cations || Comparison OF polarizability OF anions || Applications OF fajan's rule-comparison OF covalent characters || Comparison OF thermal stability

Which of the following is NOT CORRECT for both lanthanoids and actinoids?

(a) When a chromite ore (A) is fused with an aqueous solution of sodium carbonate in free excess of air, a yellow solution of compound (B) is obtained. This solution is filtered and acidified with sulphuric acid to form compound (C). Compound (C) on treatment with solution of KCl gives orange crystals of compound (D). Write the chemical formulae of compounds A to D. (b) Describe the cause of the following variations with reSQPect to lanthanoids and actinoids: (i) Greater range of oxidation states of actinoids as compared to lanthanoids. (ii) Greater actinoid contraction as compared to lanthanoid contraction. (iii) Lower ionisation enthalpy of early actinoids as compared to the early lanthanoids.

Lanthanoids and actinoids are f-block elements in which the last electron enters the anti-penultimate energy level. The most common oxidation state of lanthanoids is +3, though +2 and +4 oxidation states are exhibited by some of the elements. In lanthanoid series, there is a progressive decrease in atomic and ionic radii, known as lanthanoid contraction. Unlike lanthanoids, actinoids show a large number of oxidation states. Which out of La(OH)_3 and Lu(OH)_3 is more basic?

STATEMENT-1 : Lanthanoids show less oxidation states than actinoids and STATEMENT-2: 4f subshell is dieperseated than 5f .

Write four points of distinction between Lanthanoids and Actinoids

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.