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

Feb 12, 2017

$\text{1s"^2"2"^2"2p"^6"3s"^2}$

#### Explanation:

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:

$\text{1s"^2"2"^2"2p"^6"3s"^2}$

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

Feb 12, 2017

$1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2}$

#### Explanation:

The element with atomic number 12 is Magnesium. It has 12 electrons:
2 electrons in the 1st orbital in an s-shell
8 electrons in the 2nd orbital: 2 in an s-shell and 6 in the p-shell
and 2 in the 3rd orbital, an s-shell.

You can use the Aufbau principle to help with the order.