8.30 Compare the chemistry of actinoids with that of the lanthanoids with special reference to: 

(i) Electronic configuration

(ii) Atomic and ionic sizes

(iii) Oxidation state

(iv) Chemical reactivity.

<p><strong>8.30&nbsp;</strong></p><table><tbody><tr><td width="200"><p>&nbsp;</p></td><td width="200"><p><strong>Lanthanoids</strong></p></td><td width="200"><p><strong>Actinoids</strong></p></td></tr><tr><td width="200"><p>Electronic Configuration</p></td><td width="200"><p>It is represented by [Xe]4f^x5d^y6s^2, where x varies from 0 to 14 and y= 0 or 1</p></td><td width="200"><p>It is represented by [Rn]5f^x6d^y7s², where x varies from 0 to 14 and y= 0</p><p>or 1.</p></td></tr></tbody></table><table><tbody><tr><td><p>Oxidation state</p></td><td><p>Generally shows +3 oxidation state only in some cases it is +2 or +4 but never greater than +4</p></td><td><p>It has +3 oxidation state but also shows higher oxidation states such as +4, +5, +6, +7.</p></td></tr><tr><td><p>Atomic and ionic sizes</p></td><td><p>Ionic radii of M³⁺ions decrease in size with increase in atomic number this is called as lanthanoid contraction.</p></td><td><p>There is a gradual decrease in the size of M³⁺ ions across the series, this is known as actinoid contraction.</p></td></tr><tr><td><p>Chemical Reactivity</p></td><td><p>Lanthanoids are less reactive in nature and form oxides, sulphides, nitrides etc. They have a lesser tendency to form complexes.</p></td><td><p>They are highly reactive in nature when they are in the finely divided state. They have a higher tendency to form complexes and even react with non-metals at moderate temperature.</p></td></tr></tbody></table><p>Actinoid Contraction &gt; Lanthanoid contraction</p><p>Lanthanoids show lanthanoid contraction due to which their size is quite small as compared to actinoids although there is actinoid contraction also lanthanoid contraction has more impact on elements as there is one shell less than actinoids, so lanthanoids have less tendency to lose an electron and to undergo any reaction like the formation of oxide etc.</p>

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