Question

The first ionization energy of lithium will be :

• A. greater than $Be$
• B. less than $Be$
• C. equal to that of $Na$
• D. equal to that of $F$

Answer 1

The correct option is B less than $Be$

On going from left to right in a period I.P increases due to increase in effective nuclear charge. Thus, I.P of $Li$ is less than that of $Be$.