Question

What are the four quantum numbers for the last electron in #Fe^(3+)?

Answer 1

For iron, `Z=26`.......

Explanation:

And so we would write the following electronic configuration with respect to the atom....

`1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(2)3d^(6)`

But upon oxidation.......we gets `Fe^(3+)`, and the standard electronic configuration is.....
`{1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(5)}^(3+)`

So the last electron is from one of the (degenerate!) `"d-orbitals...."`

And thus...........

`n=3; l=2 "(i.e. we have d-orbitals with 2 nodal planes)";m_l=-2,-1,0,1,or2; m_s=+-1/2`