How does the electronic configuration of an atom relate to its position in the Modern Periodic Table?

(N/A) The position of an element in the Modern Periodic Table is determined by its electronic configuration:
$1$. The number of valence electrons determines the group number. Elements with the same number of valence electrons are placed in the same group (column).
$2$. The number of shells occupied by electrons determines the period number. Elements in the same period have the same number of electron shells.
$3$. As we move across a period,the number of valence electrons increases by one,while the number of shells remains constant.