Compare the properties of lanthanoids and actinoids.

Lanthanoids are-

(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 respect 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.

Write one similarity and one difference between the chemistry of lanthanoids and that of actinoids.

(i)with reference to structural variability and chemical reactivity write the differences between lanthanoids and actinoids (ii) Name a member of the lanthanoid series which is well known to exhibit +4 oxidation state

Compare the properties of covalent and electrovalent compounds on the following . (A) solubility . (B) Structure .

(a) Account for the following, (i) Transition metals show variable oxidation states. (ii) Zn, Cd and Hg are soft metals. (c) E^(@) value for the Mn^(3+)//Mn^(2+) couple is highly positive (+1.57V) as compared to Cr^(3+)//Cr^(2+) (b) Write one similarity and one difference the chemistry of lanthanoid and actinoid elements.

(a) Account for the following : (i) Transition metals form large number of complex compounds (ii) The lowest oxide of transition metal is basic whereas the highest oxide is amphoteric or acidic (iii) E^(@) value for the Mn^(3+)//Mn^(2+) couple is highly positive (+1.57V) as compare to Cr^(3+)//Cr^(2+) (b) Write one similarity and one difference between the chemistry of lanthanoid and actinoid elements.

Reason of lanthanoid contraction is

Define lanthanoids. Give three differences between lanthanoids and actinoids.

Compare the properties of electrons, protons and neutrons.