# How do you draw electron orbital diagrams?

Jul 25, 2016

You use lines for orbitals and arrows for electrons.

Something simple is $\text{He}$, whose configuration is $1 {s}^{2}$. So, you fill one orbital with two electrons, as is the maximum for one $s$ orbital.

$1 {s}^{2}$:

$\textcolor{w h i t e}{\left[\begin{matrix}\textcolor{b l a c k}{\underline{\uparrow \downarrow}} \\ \textcolor{b l a c k}{1 s}\end{matrix}\right]}$

If you add more orbitals, you include their relative energies. Say you have $\text{Li}$. Then you have a $2 s$ orbital at a (significantly) higher energy.

$1 {s}^{2} 2 {s}^{1}$:

$\textcolor{w h i t e}{\left[\begin{matrix}\textcolor{b l a c k}{\underline{\uparrow \textcolor{w h i t e}{\downarrow}}} \\ \textcolor{b l a c k}{2 s}\end{matrix}\right]}$

$\text{ }$
$\text{ }$

$\textcolor{w h i t e}{\left[\begin{matrix}\textcolor{b l a c k}{\underline{\uparrow \downarrow}} \\ \textcolor{b l a c k}{1 s}\end{matrix}\right]}$

With $\text{B}$, you introduce the $2 p$ orbital, which is even higher in energy than the $2 s$. There are also three of them, instead of just one.

$1 {s}^{2} 2 {s}^{2} 2 {p}^{1}$:

$\textcolor{w h i t e}{\left[\begin{matrix}\textcolor{b l a c k}{\underline{\uparrow \textcolor{w h i t e}{\downarrow}}} \\ \textcolor{b l a c k}{2 {p}_{x}}\end{matrix}\right]} \textcolor{w h i t e}{\left[\begin{matrix}\textcolor{b l a c k}{\underline{\textcolor{w h i t e}{\downarrow} \textcolor{w h i t e}{\downarrow}}} \\ \textcolor{b l a c k}{2 {p}_{y}}\end{matrix}\right]} \textcolor{w h i t e}{\left[\begin{matrix}\textcolor{b l a c k}{\underline{\textcolor{w h i t e}{\downarrow} \textcolor{w h i t e}{\downarrow}}} \\ \textcolor{b l a c k}{2 {p}_{z}}\end{matrix}\right]}$

$\textcolor{w h i t e}{\left[\begin{matrix}\textcolor{b l a c k}{\underline{\uparrow \downarrow}} \\ \textcolor{b l a c k}{2 s}\end{matrix}\right]}$

$\text{ }$
$\text{ }$

$\textcolor{w h i t e}{\left[\begin{matrix}\textcolor{b l a c k}{\underline{\uparrow \downarrow}} \\ \textcolor{b l a c k}{1 s}\end{matrix}\right]}$

Filling up the $2 p$ orbitals some more, let's look at $\text{F}$. You add one electron at a time to each $p$ orbital to maximize total spin, as per Hund's Rule, and then pair them up afterwards.

$1 {s}^{2} 2 {s}^{2} 2 {p}^{5}$:

$\textcolor{w h i t e}{\left[\begin{matrix}\textcolor{b l a c k}{\underline{\uparrow \downarrow}} \\ \textcolor{b l a c k}{2 {p}_{x}}\end{matrix}\right]} \textcolor{w h i t e}{\left[\begin{matrix}\textcolor{b l a c k}{\underline{\uparrow \downarrow}} \\ \textcolor{b l a c k}{2 {p}_{y}}\end{matrix}\right]} \textcolor{w h i t e}{\left[\begin{matrix}\textcolor{b l a c k}{\underline{\uparrow \textcolor{w h i t e}{\downarrow}}} \\ \textcolor{b l a c k}{2 {p}_{z}}\end{matrix}\right]}$

$\textcolor{w h i t e}{\left[\begin{matrix}\textcolor{b l a c k}{\underline{\uparrow \downarrow}} \\ \textcolor{b l a c k}{2 s}\end{matrix}\right]}$

$\text{ }$
$\text{ }$

$\textcolor{w h i t e}{\left[\begin{matrix}\textcolor{b l a c k}{\underline{\uparrow \downarrow}} \\ \textcolor{b l a c k}{1 s}\end{matrix}\right]}$

And that should cover the general idea.