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

First I.E. 5d elements are higher than those of 3d and 4d elements. This is due to 1) greater effective nuclear charge action on outer valence electrons. 2) greater effective nuclear charge is experience because of weak shielding effect of 4-f orbitals

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.

Assertion : The order of atomic radii of Cu, Ag and Au is Cu lt Ag ~~ Au . Reason : The atomic radii of 4d series elements are larger than those of 3d series elements but generally the radii of 4d and 5d series elements are almost identical.

Assertion : The order of atomic radii of Cu, Ag and Au is Cu lt Ag ~~ Au . Reason : The atomic radii of 4d series elements are larger than those of 3d series elements but generally the radii of 4d and 5d series elements are almost identical.

The 3d-series elements ranges

Give reason : First ionisation enthalpies of 5d elements are higher than those of 3d and 4d elements.

Explain why the first ionisation enthalpies of 5d elements are much higher as compared to those of 3d and 4d elements.