The arrangement of electrons in atoms is important because it determines how the atom will with other atoms.

 interact    

Explanation:

The arrangement of electrons is done by using the octet rule , which helps to determine the stability of the atom , as only specific configuration of electrons are stable in nature and hence, all the atoms tries to attain the stability by reaching to that specific stable electron configurations.

In case the electronic configuration is not stable , then the atom tries to bond or interact with other atoms to attain stability.

Hence, from the information of the question,

The arrangement of electrons is around the nucleus of the atom is important , as it determines how the atom will interact with other atoms.