Correct order of first IP among following elements $\mathrm{Be}, \mathrm{B}, \mathrm{C}, \mathrm{N},…

Correct order of first IP among following elements $\mathrm{Be}, \mathrm{B}, \mathrm{C}, \mathrm{N}, \mathrm{O}$ is
  1. $\quad \mathrm{B} < \mathrm{Be} < \mathrm{C} < \mathrm{O} < \mathrm{N}$
  2. $\quad \mathrm{B} < \mathrm{Be} < \mathrm{C} < \mathrm{N} < \mathrm{O}$
  3. $\quad \mathrm{Be} < \mathrm{B} < \mathrm{C} < \mathrm{N} < \mathrm{O}$
  4. $\quad \mathrm{Be} < \mathrm{B} < \mathrm{C} < \mathrm{O} < \mathrm{N}$

Solution

$\mathrm{Be}-1 s^{2} 2 s^{2} ; \mathrm{B}-1 s^{2} 2 s^{2} 2 p^{1} ; \mathrm{C}-1 s^{2} 2 s^{2} 2 p^{2}$
$\mathrm{N}-1 s^{2} 2 s^{2} 2 p^{3 ;} \mathrm{O}-1 s^{2} 2 s^{2} 2 p^{4}$. IP increases
along the period. But IP of $\mathrm{Be}>\mathrm{B}$. Further IP of $\mathrm{O} < \mathrm{N}$ because atoms with fully or partly filled orbitals are most stable and hence have high ionisation energy. .

Asked in: JEE-TOPICTESTS-CHEMISTRY

Practice more CLASSIFICATION OF ELEMENTS AND PERIODICITY IN PROPERTIES questions on Aicharya