In what way are the observed oxidation states of the lanthanides related to their electronic configurations?
The lanthanum (At. No. 57) has the outer electronic configuration 5d1 6s2 and has the oxidation number 3.
Similarly next element cerium (At. No. 58) has the outer electronic configuration 4f15d16s2 and has the oxidation number 4. Thus we see that the oxidation number of lanthanides are well related to electronic configurations of lanthanides.
Assign reasons for the following:
The enthalpies of atomisation of transition metals are high.
How is the variability in the oxidation states of transition metals different from that of the nontransition metals? Illustrate with examples.
Describe the general characteristics of the transition elements with special reference to their tendency to:
(i) Exhibit paramagnetism.
(ii) Form complex compounds.
(iii) Their catalytic behaviour.