Q. For the second period elements the correct increasing order of first ionisation enthalpy is :
A) Li < Be < B < C < N < O < F < Ne
B) Li < B < Be < C < O < N < F < Ne
C) Li < B < Be < C < N < O < F < Ne
D) Li < Be < B < C < O < N < F < Ne
Explanation
[Solution] Be ($2s^2$) > B and N (half-filled 2p) > O give Li < B < Be < C < O < N < F < Ne. Answer (2).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.