Question

can every body tell me?? why the electronic confriguration of Cr and Sc is Different..??

Answer 1

Why or how?

Why is because it gives the molecule more stability. It takes higher amount of energy for it to obtain an electron in it's sub-shell. More thermodynamically favorable since Sc has a bigger atomic radius than Cr, therefore, leaving the electrons less shielded.
How? You might want to write out the electron configuration for both:

\[Sc = [Ar]4s^23d^1, Cr = [Ar]4s^13d^5\]