Why zn ,cd hg are not transition elemants

The electronic configurations of Zn, Cd and Hg are represented by the general formula (n-1)d10 ns2. The orbitals in these elements are completely filled in the ground state as well...

because these have fully filled orbital in ground state as well as in excited state. while transition metals are those which have vacant d orbitals

They are d10 system

since zn, cd & Hg has fully filled d10 configuration in their ground state therefore they do not show property of typically transistion elements and are not regarded as transition...