[gayathri1989]

hello,

what is the configuration of chromium and which rule it deviates from ex:hunds rule etc.

[Donaldson Tan]

3d5 and 3d10 are very stable configuration

3d4 4s2 will change to 3d5 4s1 because of the extra stability conferred by 3d5.

[2810713]

 4s orbital , according to n+l rule , should get filled before 3d .
this will lead to 3d4  state which is unsymmetrical than 3d5 this is most symmetrical possible state, thus  to get maximum possible symmetry in order to get max. posible stability, the 4s electron is raised to 3d level to get 3d5 state.

Sorry, I have answered in quite complecated way.

thanx

hrushikesh