Question

The correct order of first ionization enthalpy values of the following elements is :
(A) O (B) N (C) Be (D) F (E) B
Choose the correct answer from the options given below :

• A. B < D < C < E < A
• B. E < C < A < B < D
• C. C < E < A < B < D
• D. A < B < D < C < E

Answer 1

The Correct Option is B

First ionization enthalpies are ordered by periodic trends. Generally, ionization enthalpy rises across a period due to increased nuclear charge and falls down a group as atomic size grows. Elements with stable electron configurations (half-filled or fully-filled orbitals) also exhibit higher ionization enthalpies.

The standard trend for ionization enthalpy in the periodic table is:

\( \text{Li} < \text{B} < \text{Be} < \text{C} < \text{O} < \text{N} < \text{F} < \text{Ne} \)

For the elements provided:

\( \text{E (B)} < \text{C (Be)} < \text{A (O)} < \text{B (N)} < \text{D (F)} \)

Therefore, the correct sequence of first ionization enthalpy values is:

\( \text{E (B)} < \text{C (Be)} < \text{A (O)} < \text{B (N)} < \text{D (F)} \)