In these elements the inner d orbitals are progressively filled The f-block is placed
outside at the bottom of the periodic table and in the elements of this block, 4f and
5f orbitals are progressively filled Corresponding to the filling of 3d, 4d and 5d orbitals, three series of transition
elements are well recognised All the transition elements exhibit typical metallic properties
such as –high tensile strength, ductility, malleability, thermal and electrical conductivity
and metallic character