Question

iron
express your answer in complete form, in order of increasing orbital. for example, 1s²2s² would be entered as 1s^22s^2.

Explanation:

Step1: Recall iron's atomic number

Iron (Fe) has atomic number 26.

Step2: Write electron - configuration

Using the Aufbau principle, Pauli - exclusion principle and Hund's rule, the electron - configuration is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{6}$.

Answer:

$1s^22s^22p^63s^23p^64s^23d^6$