The first ionisation energies of the elements of the first transition series `(TitoCu)`

Options

A. increases as the atomic number increases
B. decreases as the atomic number increases
C. do not show any change as the addition of electrons takes place in the inner (n-1) d-orbitals
D. increases from Ti to Mn and then decreases from Mn to Cu..

Answer

A

Explanation

In case of transition metals, the addition of increasing number of d-electrons provides a screening effect. Thus, shields the increasing nuclear charge and expansion of d-orbitals then to oppose each other. On account of these two opposing effect, the ionization energies increase rather slowly on moving along the period.