Explain Fe electronic configuration

Fe is not a noble metal. Firstly, the exact configuration of Fe is not 2,8,8,8. Since the second last shell should have 18 electrons for it to be a noble metal. All the inner shells in this case K,L,M shells have to be completely filled with electrons. It is not the case with this configuration. K can have a maximum of 2 electrons, L can have a maximum of 8 electrons, M can have a maximum of 18 electrons.

Don't get confused. You will be studying the exact way of writing the configuration of an atom in higher classes.