# What is the abbreviated electron configuration for cobalt?

[Ar] $4 {s}^{2} 3 {d}^{7}$

#### Explanation:

To write abbreviated electron configurations you need to start at the selected element and go down in atomic numbers to find the next smallest noble gas.

Write the symbol for this noble gas in [brackets] then pick up writing the electron configuration like you would if you were writing a full electron configuration.

Here is a video which discusses how to write a shortcut electron configuration for the elements magnesium and lead.

Hope this helps!