Question

Why is the electron configuration of chromium [Ar]3d54s1 and not [Ar]3d44s2, and why is the 3d sublevel written before the 4s sublevel even though it is higher in energy?

Answer 1

as to half fill the d orbital in Cr one electron from s orbital goes to 3d.

and as in transition elements the filling of electron is first in 4s and then to 3d but it loss electron first in 3d then to 4s

Answer 2

Answer:

Explanation:

as to half fill the d orbital in Cr one electron from s orbital goes to 3d.

and as in transition elements the filling of electron is first in 4s and then to 3d but it loss electron first in 3d then to 4s