2 gives the values of the first three ionisation enthalpies of the first
series of transition elements These values show that the successive
enthalpies of these elements do not increase as steeply as in the case
of non-transition elements The variation in ionisation enthalpy along
a series of transition elements is much less in comparison to the variation
along a period of non-transition elements The first ionisation enthalpy,
in general, increases, but the magnitude of the increase in the second
and third ionisation enthalpies for the successive elements, is much
higher along a series