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.
An element of atomic number 16 has the electronic configuration 2, 8, 6.
Group number of the given element depends on the number of valence electrons present. The given element will be placed in group 16.
The number of shells filled determines the period in which the element will be placed. Thus, the given element will be placed in the third period.
The element has six valence electrons. The valency of elements that have more than four valence electrons is determined by subtracting the number of valence electrons from eight.
Thus, Valency = 8 - 6 = 2.