How it can be proved that the basic structure of the Modem Periodic Table is based on the electronic configuration of atoms of different elements?

Modern periodic table:

• The modern periodic law states that the periodicity of elements is a function of their atomic numbers.
• Its basic structure is based on the electronic configuration of atoms of different elements consisting of groups and periods.
• The electronic configuration of an element can be used to determine the location of that element in the periodic table.
• The number of valence electrons determines the group and the number of shells determines the period.

For example the configuration of $\mathrm{Li}$ is = $1{\mathrm{s}}^{2}2{\mathrm{s}}^1$

• This shows that the element Lithium belongs to the 2nd period and 1st group in the Periodic Table.