Question

Which of the following p-block element will have highest ionization enthalpy?

• A. Carbon (C)
• B. Oxygen (O)
• C. Nitrogen (N)
• D. Fluorine (F)

Answer 1

The correct option is D Fluorine (F)


The given elements belong to the 2nd period. As we move from left to right of the periodic table, the ionization enthalpy increases. The electronic configuration of the given elements is:

C - $1s^{2}2s^{2}2p^2$
O- $1s^{2}2s^{2}2p^4$
N - $1s^{2}2s^{2}2p^3$
F- $1s^{2}2s^{2}2p^5$

The number of electrons in the outermost orbit is directly proportional to the ionization enthalpy of the element. Therefore, fluorine has the highest ionization enthalpy.