The trend in ionisation enthalpy of transition element is not regular because

Explain ionisation enthalpy of group 14 elements .

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.

Discuss and compare the trend in ionisation enthalpy of the elements of group 1 with those of group 17 elements.

Explain the trends in ionisation enthalpies of d-block elements.