Question

In which of the following pairs, the first member has higher first ionization energy?

• A. $N,O$
• B. $B,Be$
• C. $Al,Ga$
• D. $Cl,F$

Answer 1

The correct option is A $N,O$

Due to stable half filled p-orbital the nitrogen molecule does not want to lose electrons easily. Therefore its first ionization potential is greater than that of oxygen but less than fluorine.. Because Nitrogen has a higher affinity for its electrons than Oxygen does for the first ionization level.

Hence option A is correct answer.