explain how the electron configurations of the atoms of the transition metal differ from the atom of metals ？?

Transitional metals have multiple oxidation states, i.e. can have multiple valencies.

This means that electron configuration in the outermost shell can be different in different atoms. For example, copper(II) has two electrons in it's outermost shell. Copper(III) has three.

Other metals in group 1, 2, and 3, have a fixed valency. This means that Group 1 metals have one outer electron, Group 2 have two outer electrons, e.t.c