Question

Why generally zn cd and hg are not considered as transition element?

Answer 1

first we know about what is transition element
these are those element The transition elements are those elements having a partially filled d or f subshell in any common oxidation state. The term "transition elements" most commonly refers to the d-block transition elements. The 2B elements zinc, cadmium and mercury do not strictly meet the defining properties, but are usually included with the transition elements because of their similar properties.