Question

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.

Answer 1

The systematic arrangement of electrons in the orbitals is called electronic configuration. The electronic configuration increases in the outermost valence shell which relates to its position in the modern periodic table.

The electronic configuration of the element with atomic number 16 is 2,8,6. This indicates that the element belongs to group 16 and period 3 as the number of valence shell is 3 and valence electrons is 6.

The valency is calculated as follows:

• Firstly, write the electronic configuration of the element.
  
• If the valence electrons are less than or equal to four then the valency is the number of valence electrons.
  
• If the valence electrons are more than 4 then valency is (8 $-$ number of valence electrons).