What is the abbreviated electron configuration for cobalt?

Hint: We have to find the nearest noble gas element of the atom to write the abbreviated electronic configuration of an atom in the periodic table. We should know the atomic number of an element to write the electronic configuration.

Complete answer:
- In the question it is given to write the abbreviated electron configuration of the cobalt.
- We should know the atomic number of cobalt to write the electronic configuration of it.
- The atomic number of cobalt is 27 means cobalt contains 27 electrons in it.
- The general electronic configuration of cobalt is $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}4{{s}^{2}}3{{d}^{7}}$ .
- We have to find the nearest noble gas element to cobalt to write the abbreviated electronic configuration.
- The noble gas which is nearer to cobalt is argon with an atomic number of 18.
 - The electronic configuration of argon is $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}$ .
- Therefore we can write the abbreviated electronic configuration of the cobalt and it is as follows.
\[[Ar]4{{s}^{2}}3{{d}^{7}}\]
- Means we can replace the electronic configuration of the cobalt up to 3p orbital by using the symbol [Ar].
- Abbreviated electronic configuration is the shortest way to write the electronic configuration of the elements.

Note:
By using the abbreviated way we can decrease the length of the electronic configuration of the elements which have very lengthy electronic configuration. Especially we can use the abbreviated electronic configuration to write the electronic configuration of the d-block and f-block elements.