Why elements of group 12 are not considered as transition elements ?

Transition elements are

Why Zn, Cd and Hg are not considered as typical transitions elements ?

Read the passage given below and answer the question: The d block elements are the 40 elements contained in the four rows of ten columns (3-12) in the periodic table. As all the d block elements are metallic, the term d-block metals is synonymous. This set of d-block elements is also often identified as the transition metals, but sometimes the group 12 elements (zinc, cadmium, mercury) are excluded from the transition metals as the transition elements are defined as those with partly filled d or f shells in their compounds. Inclusion of the elements zinc, cadmium and mercury is necessary as some properties of the group 12 elements are appropriate logically to include with a discussion of transition metal chemistry. The term transition element or transition metal appeared to derive from early studies of periodicity such as the Mendeleev periodic table of the elements. His horizontal table of the elements was an attempt to group the elements together so that the chemistry of elements might be explained and predicted. In this table there are eight groups labeled I-VIII with each subdivided into A and B subgroups. Mendeleev recognized that certain properties of elements in Group VIII are related to those of some of the elements in Group VII and those at the start of the next row Group I. In that sense, these elements might be described as possessing properties transitional from one row of the table to the next. (source: Winter, M. J. (2015). D- block Chemistry (Vol. 27). Oxford University Press, USA.) In the following question, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the choices on the basis of the above passage. Assertion: Group 12 elements are not considered as transition metals. Reason: Transition metals are those which have incompletely filled d shell in their compounds.

(a) What are transition elements ? Which of the d-block elements are not regarded as transition elements ? (b) In what way the electronic configurations of transition elements are different from those of representative elements ?

Which of the d-block elements are not referred to as the transition elements ?

The group numbers of transition elements

Which of the following does not considered as transition element ?