Explain the following observations : (i) Many of the transition elements are known to form interstitial compounds . (ii) There is a general increase in density from titanium (Z =22) to copper (Z = 29). (iii) The members of the actinoid series exhibit a larger number of oxidation states than the corresponding members of the lanthanoid series.

Explain the following observations : (i) Many of the transition eleme

1.	Explain the following observations : (i) Many of the transition elements are known to form interstitial compounds . (ii) There is a general increase in density from titanium (Z =22) to copper (Z = 29). (iii) The members of the actinoid series exhibit a larger number of oxidation states than the corresponding members of the lanthanoid series.
Answer» Solution :In case of actinoids, 5F, 6d and 7s subshells have compareable energies. Therefore, actinoids EXHIBIT +3, +4, +5, +6 and +7 oxidation states DUE to the participiation of 5f, 6d and 7s electrons in bond formation.