How will you account for the following : (i) All scandium salt are white.
(ii) The first ionisation enthalpy of the 5d transition elements are higher than those of 3d and 4d transition elements in respective group.

First IE of 5d seties element are higher than those of 3d and 4d series elements. This is due to:

Higher values of ionisation energies of the 5d-transition elements are consistent with the:

The second ionisation enthalpy of the elements of group 1 are higher than those of elements of group 2 . Explain.

(a) What is Lanthanoid contration ? What are its important effects ? (b) Account for the following : (i) Zn^(2+) salts are white while Ni^(2+) salts are coloured. (ii) Ionisation enthalpies of 5d series elements are higher than the corresponding 3d series elements