of the d-Block

of the d-Block Sc Ti Co Ni Cu Zn Z s 1st Series Table . : Electronic Configurations of outer orbitals of the Transition Elements (ground state) The electronic configurations of outer orbitals of Zn, Cd, Hg and Cn are represented by the general formula (n- ) d n s . The orbitals in these elements are completely filled in the ground state as well as in their common oxidation states. Therefore, they are not regarded as transition elements. The d orbitals of the transition elements protrude to the periphery of an atom more than the other orbitals (i.e., s and p ), hence, they are more influenced by the surroundings as well as affect the atoms or molecules surrounding them. In some respects, ions of a given d n configuration (n = – ) have similar magnetic and electronic properties. With partly filled d orbitals these elements exhibit certain characteristic properties such as display of a variety of oxidation states, formation of coloured ions and entering into complex formation with a variety of ligands. The transition metals and their compounds also exhibit catalytic property and paramagnetic behaviour. All these characteristics have been discussed in detail later in this Unit. There are greater similarities in the properties of the transition elements of a horizontal row in contrast to the non-transition elements. However, some group similarities also exist. We shall first study the general characteristics and their trends in the horizontal rows (particularly d row) and then consider some group similarities. 2nd Series Y Zr Nb Mo Tc Ru Rh Pd Ag Cd Z s d 3rd Series La Hf Ta W Re Os Ir Pt Au Hg Z s d Ac Rf Db Sg Bh Hs Mt Ds Rg Cn Z s d 4th Series On what ground can you say that scandium ( Z = ) is a transition element but zinc ( Z = ) is not? On the basis of incompletely filled d orbitals in case of scandium atom in its ground state ( d ), it is regarded as a transition element. On the other hand, zinc atom has completely filled d orbitals ( d ) in its ground state as well as in its oxidised state, hence it is not regarded as a transition element.