All transition element are d- block element but all d- block element are not transition elements Explain.

Explanation

Element in which the last electron enters any one of the five d- orbitals of their respec tive penultimate shells are called d-block elements. In the light of this definition Zn , Cd, Hg and Cn cannot be regarded as d- block element since last electron in them enters the s-orbital of their respective ultimate shells rather than the d- orbital of their respective penultimate shells . therefore these element should be regarded as s- block element .But the properties of these element resemble more the d-block rather than s- block element ( refer to Ans to Q.1 page `3//61`) . Therefore to make the study of periodic classification of element more rational they are studied along with d-block element . Thus on the basis of properties all transition element are d-block element but on the basis of electronic configuration all d-block element are not a transition elements