The for cobalt (Co) is ##1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^7##, determined by the position of the element on

The for cobalt (Co) is ##1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^7##, determined by the position of the element on .

Cobalt is an will end in a d block. Cobalt is in the 7th column of the d block and therefore has 7 d electrons ##d^7##. The element cobalt can be found in the 4th row or 4th energy level of the periodic table. However, the inner transition metals or d block are always one level lower than the energy level that the element is found on meaning the electron configuration for cobalt must end as ##3d^7##.

All electron levels must be filled above that point. So the entire configuration is as follows: ##1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^7##

As another example, Argon is a noble gas and has each of the electron levels filled. Using you can write the s,p,d,f configuration in an abbreviated form.

[Ar] can represent ##1s^2 2s^2 2p^6 3s^2 3p^6 ##

Making the configuration: [Ar] ##4s^2 3d^7##

Here is a You Tube video on determining electron configurations: