Question

The following questions consist of two statements. Select the correct option for these statements:
Statement 1: The first ionization energy of $Be$ is greater than that of $B$.
Statement 2: $2p$-orbital is lower in energy than $2s$.

• A. Both the statements are CORRECT, and Statement II is the CORRECT explanation of Statement I
• B. Both the statements are CORRECT, and Statement II is not a CORRECT explanation of Statement I
• C. If Statement I is CORRECT, but Statement II is INCORRECT
• D. If Statement I is INCORRECT, but Statement II is CORRECT

Answer 1

The correct option is C If Statement I is CORRECT, but Statement II is INCORRECT

Electronic configuration of $Be$: $(1s^2,2s^2)$ and
Electronic configuration of $B$: $(1s^2,2s^2,2p^1)$
Statement $1$ is correct: $Be:(1s^2,2s^2)$ has stable electronic configuration, removing an electron requires more energy than the same for $B:\left(2p^1\right)$, which has a single valence electron in $2p$-orbital which can be easily removed.
According to the Aufbau principle, the energy of $2s$-orbital is lower than that of $2p$-orbital, thus statement $2$ is incorrect.