# What is the shorthand electron configuration for silicon?

Jul 20, 2017

Longhand Electron Configuration:

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

Noble Gas Configuration (shorthand):

$\left[N e\right] 3 {s}^{2} 3 {p}^{2}$

#### Explanation:

We could have easily written out in normal electron configuration, but since this would made us go through every single $s , p , d \mathmr{and} f$ orbitals, we use something called the Noble Gas configuration.

The noble gas configuration of an element is just an easy way of writing it using the PREVIOUS noble gas. All elements in the 18th group are considered noble gases. This is because they all have their outer electrons filled.

Because of this, we'll use the previous noble gas from silicon.

We start out by listing the noble gas:

$\left[N e\right]$

From there, work to the right and use an electron configuration chart to know which orbital to start off with. In this case, we go automatically to the $3 {s}^{2}$ orbital, and then to the $3 {p}^{2}$ one since we are on the third period.

$3 {p}^{2}$ signifies it stops on the second electron in the third $p$ orbital. If you were to start at Neon $\left(N e\right)$ and work your way through the orbitals using this sort of "map", you would land on Silicon again. This is one way of writing electron configurations!

The longhand electron configuration for this element would have been:

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

Once again we land on the $3 {p}^{2}$ at the end, which helps us to identify the element we're looking for. This would have taken a little bit longer to do (although not much longer than the noble gas electron configuration).