What are 'd' and 'f' block elements ?

Explanation

The d-block elements are the elements in which the last electron enters the d orbital of the penultimate shell i.e., (n-1) orbital, where n is the outermost shell and the elements in which the differentiating electron (last electron ) enters in to (n-2) f-orbital are known as f-block elements. In these elements differentiating electron enters into prepenultimate shell.