The electronic configuration is written to describe the presence of electrons in different subshells of an atom.
Based on various data obtained while writing the electronic configuration of an atom, the element is placed in the group and period to which the element must belong.
The number of subshells depends upon the number of electrons.
Argon is a noble gas that has 18 electrons and its electronic configuration is:
The above written electronic configuration shows that the maximum number of shells is 3.