Which one of the following orders is correct | vedclass

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(C) The first ionisation energy $(IE_1)$ generally increases across a period from left to right due to an increase in effective nuclear charge. For th

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$B < Be < O < N$

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(C) The first ionisation energy $(IE_1)$ generally increases across a period from left to right due to an increase in effective nuclear charge. For the second period elements,the expected order is $Li However,there are exceptions due to stable electronic configurations. The actual order for the given elements is $B $1$. The $IE_1$ of $B$ $(1s^2, 2s^2 2p^1)$ is lower than $Be$ $(1s^2, 2s^2)$ because the electron in $B$ is removed from a $2p$ orbital,which is more shielded and further from the nucleus than the $2s$ orbital of $Be$. $2$. The $IE_1$ of $O$ $(1s^2, 2s^2 2p^4)$ is lower than $N$ $(1s^2, 2s^2 2p^3)$ because $N$ has a stable half-filled $2p$ subshell,which requires more energy to remove an electron.

Which one of the following orders is correct for the first ionisation energies of the elements?

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