The electronic configuration of an element gives the information of valence electrons and number of shell present in the element. The modern periodic table has 18 verticle columns called groups and 7 horizontal raws called periods. In the modern periodic table, atoms with similar electronic configurations are placed in the same column, hence, the number of valence electrons remains the same in the group. We get the information of group number after knowing valence electrons. Number of shells present in an element is equal to period number. Thus, by knowing electronic configuration we know the group number and period number of an element, which is the position of element in periodic table.