Why is the iron KLMN configuration 2,8,14,2 and not 2,8,8,8?

The electron configuration of iron (Fe) is actually 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶, which corresponds to the ground state electron configuration. The KLMN notation you provided is a simplified representation that only shows the number of electrons in each shell (K, L, M, and N).

In the KLMN notation, the numbers represent the maximum number of electrons that can occupy each shell. The K shell can hold a maximum of 2 electrons, the L shell can hold a maximum of 8 electrons, the M shell can hold a maximum of 18 electrons, and the N shell can hold a maximum of 32 electrons. However, it's important to note that the actual number of electrons in each shell depends on the atomic number of the element.

For iron (atomic number 26), the first two electrons occupy the 1s subshell, the next two electrons occupy the 2s subshell, the following six electrons occupy the 2p subshell, and so on. The filling pattern continues until we reach the 3d subshell, where iron has 6 electrons. Since the 3d subshell can accommodate a total of 10 electrons, there are still 4 remaining electron slots in the 3d subshell for iron. Therefore, the electron configuration for iron is 2, 8, 14, 2 in terms of the KLMN notation.