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 number.
Atomic number of the element = 16
Electronic configuration = 2, 8, 6
The period number is equal to the number of shells which starts filling up in it.
The atom of an element has three shells. So, the period number is 3.
The atom of an element has six valence electrons in the outermost shell. So, the group number of the element will be 16 (6 + 10).
The valency of an element is determined by the number of valence electrons present in the outermost shell. The atom of an element has six valence electrons in the outermost shell, so the valency of the element is 2.