Question

before we put electron(s) in 3d electron shell,electron shells arrange like this( 4s,3d)but as we put electron(s) in 3d they arrange like this (3d,4s). why this is happend?

Answer 1

can you help me @aaronq , @Abhisar , @ganeshie8 ?

Answer 2

because their energy is lower

Answer 3

plz explain further.@aaronq

Answer 4

what do you think @Luigi0210 , @chmvijay ?

Answer 5

i am sorry first 3d is 4s

Answer 6

1. Orbital which has the least value of (n+l) will be filled first to the electrons
can u calculate n+l values for 3d and 4s