Question

Which of the following has the highest first ionization energy?

• A. Li
• B. Be
• C. B
• D. C

Answer 1

The correct option is D

C

As we know from the definition of ionization energy and its relation with atomic radius.

(a) Atomic radius: The values of ionization potential of an element decreases as its atomic radius increases. This is because the electrostatic force of attraction between the nucleus and the outermost electron decreases as the distance between them increases. So the energy required for the removal of the electron will comparatively be less

Ionization potential $\alpha$ $\frac{1}{Atomicradius}$

$\to$ First ionization energy should increase along the period from left to right.

In a period, Li $\to$ Be $\to$ B $\to$ C. Therefore, carbon will have the highest first ionization energy.