Question

How does the electronic configuration of an atom relate to its position in modern periodic table?

Answer 1

Electronic configuration is the distribution of electrons in differnt shells.
The position of an atom/element in the periodic table is related to the number of electrons in the outermost shell.
The number of electrons in the outer most shell decides , its group while the number of shells describe the period in which it is present.
So this way electronic configuration is related to position of an element in the periodic table.

For example sodium(Na) has atomic number of 11. Its electronic configuration is 1s2 2s2 2p6 3s1. Since the outer most shell has 1 electron that means it belongs to group 1 and the outermost shel is 3rd shell , that means it belongs to period 3.
so position of Na is: group1, period 3