# How are inert gas cores used as a shorthand for electronic configuration?

May 28, 2017

Use the configuration of the inert gas core as a basis...........

#### Explanation:

For atomic lithium we have a configuration of $1 {s}^{2} 2 {s}^{1}$. We COULD use the known configuration of helium to write $\left[H e\right] 2 {s}^{1}$. All the chemistry is going to occur outside the inert gas core........

And then we go to neon, $Z = 10 : 1 {s}^{2} 2 {s}^{2} 2 {p}^{6}$, and then sodium, $Z = 11 : 1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{1}$. We have a valence electron tacked onto an inert gas core, i.e. $\left[N e\right] 3 {s}^{1}$. How does you represent magnesium? How about potassium?

Do you get the picture?

Edited for a mistake. With all these problems you SHOULD have your Periodic Table in front of you.