Answer:For Fe
Z=26
Step-by-step explanation:
1s2 2s2 2p6 3s2 3p6 4s2 3d6
Are there 26 electrons here? Why should there be 26?
So going back to the inert gas, argon ( Z=18 ), we get
[Ar] 4s2 3d6
Make sure to check your work by counting the electrons you have