# What is the shorthand electron configuration for Al?

##### 1 Answer

Given the periodic table:

We see aluminum is atomic number

When we write our electron configurations, we utilize the valence orbitals **relative to each period** to construct it, and write a superscript for the maximum number of electrons in each orbital **for each given period**.

So the full configuration is:

#color(green)(stackrel("Period 1")overbrace(1s^2) stackrel("Period 2")overbrace(2s^2 2p^6) stackrel("Period 3")overbrace(3s^2 3p^1))#

To write the **noble gas shorthand configuration**, you simply find the previous noble gas, which is **neon**, and determine which orbitals in the full configuration you've **already accounted for** by shortening the notation.

#[Ne] = 1s^2 2s^2 2p^6# .

Therefore, we just have:

#cancel(stackrel("Period 1")overbrace(1s^2) stackrel("Period 2")overbrace(2s^2 2p^6))^([Ne]) stackrel("Period 3")overbrace(3s^2 3p^1)#

#-> color(blue)([Ne] 3s^2 3p^1)#