Oxidation States of the f-Block Elements

The observed oxidation states of the lanthanide and actinide elements are given in Table 5.5. Fifteen elements are included in both series to avoid the argument as to whether La and Ac should be included and/or whether Lu and Lr are properly members of Group 3. 

The concepts of valency and oxidation state were defined and exemplified. 

The periodicity of valence of the s- and p-block elements w as described and rationalized in terms of the octet rule. Exceptions from the octet rule were discussed. These include compounds exhibiting hypervalence as a result of the expansion of the valence shell of the central atom, and compounds in which the inert pair effect is apparent, the valency of the central element being two units lower than expected for the group valency. 

The periodicities of the oxidation states of the d-block and f-block elements were described. 

Non-metallic elements which exist as (i) diatomic molecules, (ii) small polyatomic molecules, (iii) polymeric chains, (iv) polymeric sheets and (v) infinite three-dimensional arrays should have very different melting points. Explain why this should be so and give examples to support your argument. 

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Table 5 5 Oxidation states of the f-block elements those in bold red are the most stable stales, those in UaSc red are the most stable in aqueous solution in the abserxe of dioxygen...

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