The Total solution for NCERT class 6-12
Give special emphasis on the following points(i)┬аelectronicconfigurations(ii)┬аoxidation states(iii)┬аionisation enthalpiesand(iv)┬аatomic sizes.
(i) Electronicconfigurations :┬аIn 1st┬аtransitionseries, 3d-orbitals are progressively filled whereas in 2nd┬аtransitionseries, 4d-orbitals are progressively filled and in 3rd┬аtransitionseries, 5d-orbitals are progressively filled.
(ii) Oxidationsstates :┬аElements show variable oxidation statesin both the series. The highest oxidation state is equal to total number ofelectrons in тАШsтАЩ as well as тАШdтАЩ orbitals. The number of oxidation states shownare less in 5d transition series than 4d series. In 3d series +2 and +3oxidation states are common and they form stable complexes in these oxidationstates. In other series OsO4┬аand PtF6┬аareformed which are quite stable in higher oxidation state.
(iii) Ionisationenthalpies :┬аThe ionisation enthalpies in each seriesgenerally increases gradually from left to right. The ionisation enthalpy of 5dseries do not differ appreciably due to lanthanoid contraction.
(iv) Atomic sizes :┬аThe atomic sizes of 4d and 5d-series do not differappreciably due to lanthanoid contraction. The atomic radii of second and thirdseries are larger than 3d series.