Question

If the electronic configuration of calcium is (Ar)4s2 then what will be the electronic configuration of chromium and free dispositive manganese ion?......pl plz explain for 5 marks

Answer 1

Atomic no. Of chromium is 24. So it's electronic configuration should be [Ar] 4s2 3d4. But it is wrong. D subshell has 5 orbitals so if one electrons from s subshell goes to d orbital then d subshell has 5 electrons in it which makes chromium more stable. Therefore correct electronic  configuration of chromium(24) = [Ar] 4s1 3d5. Further, atomic no.  Of manganese is 25.so dipostive manganese ion has 23 electrons.hence electronic configuration of manganese=[Ar] 4s0 3d5