Taking the example of an element of atomic number 16, explain how the electronic configuration of the atom of an element relates to its position in the modern periodic table and how valency of an element is calculated on the basis of its atomic numb

Electronic configuration of element with atomic number 16 is 2, 8, 6.
Since it has 3 shells, the period number will be 3.
Since the number of valence electrons is 6, the group number will be 10 + 6 = 16.
Valency of the element will be 8 – valence electrons, i.e. 8 – 6 = 2.