Question

Explain why the atomic radius of oxygen is slightly more than that of nitrogen.

Answer 1

Hint:The distance from the centre of the nucleus of the atom to the boundary of the shells is known as the atomic radius. The trend in atomic radius is as follows: The atomic radius decreases from left to right across the period. The atomic radius increases down the group.

Complete step by step answer:
The elements given to us are oxygen and nitrogen.
In the periodic table, the elements are arranged in the increasing order of their atomic numbers.
As we move from left to right in the periodic table, the atomic number of the elements increases. By this definition, the atomic number of oxygen is slightly more than that of nitrogen.
As we move from left to right in the periodic table, the atomic radius of elements keeps on decreasing. Thus, the atomic radius oxygen should be less than that of nitrogen.
But the atomic radius of oxygen is slightly more than that of nitrogen. The reason for this is as follows:
The electronic configuration of nitrogen is $2{p^3}$. The capacity of the p-orbital is six electrons. Thus, the 2p orbital of nitrogen is half filled. Thus, the repulsion between the electrons is less.
The electronic configuration of oxygen is $2{p^4}$. The capacity of the p-orbital is six electrons. Thus, the 2p orbital of oxygen has one electron paired. Thus, the repulsion between the electrons is slightly more. Thus, the atomic radius of oxygen increases.

Note:
The atomic radius of oxygen is ${\text{67 pm}}$ while the atomic radius of nitrogen is ${\text{56 pm}}$. The reason for this is the repulsion of electrons is more in case of oxygen.