question_answer

Which one of the following elements has the highest first ionisation potential?

A)  Boron                                  

B)  Carbon

C)  Nitrogen                            

D)  Oxygen

Correct Answer: C

Solution :

                 In a period from left to right ionization potential increases, but in case of nitrogen and oxygen, nitrogen has higher value ionisation potential than oxygen. It is due to stable electronic configuration of N-atom. \[{{\,}_{7}}N=1{{s}^{2}},2{{s}^{2}}2{{p}^{3}}\] (Stable configuration) \[{{\,}_{8}}O=1{{s}^{2}},2{{s}^{2}}2{{p}^{4}}\]  (Unstable configuration) So, in the given alternates nitrogen has highest value of ionization potential.