Question

What is the electron configuration of an element with atomic number $12$?

Answer 1

The element with the atomic number $12$ is magnesium. The atomic number indicates the number of positively charged protons in each magnesium nucleus. A neutral atom has equal numbers of protons as negatively charged electrons. The electron configuration of a neutral magnesium atom is $:1s^{2}2s^{2}2p^{6}3s^2$

The Aufbau diagram can help you determine the correct order in which the electrons will fill the orbitals in an atom.