In transition elements, the shells that are incompletely filled

Element which contain incompletely filled nth shell and (n-1)th shell in their atoms (or) in their most common oxidation state (+2)  are called transition elements Zn (Z=30)....[Ne]3s23p64s23d10Zn+2....[Ne]3s23p63d10Zn and Zn+2 have  completely filled 3d10 configuration.Thus Zn is not a transition element.