Q. The correct order of decreasing first ionisation energy is
A) C > B > Be > Li
B) C > Be > B > Li
C) B > C > Be > Li
D) Be > Li > B > C
Explanation
(b)
Ionisation energy increases in a period from left to right. But ${IE}_{1}\ of\ Be\$is greater than B due to its stable configuration $(1s^{2},2s^{2})$.
Hence, the order of decreasing
${IE}_{1}is\ C > Be > B > Li$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.