Periodic Classification and Periodic Properties 2 Question 33
33. Statement $\mathbf{I}$ The first ionisation energy of $\mathrm{Be}$ is greater than that of B.
Statement II $2 p$-orbital is lower in energy than $2 s$.
(2000, (S), 1M)
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Answer:
Correct Answer: 33. (higher effective nuclear charge)
Solution:
- Statement $I$ is true $B e$ has higher first ionisation energy than $B$ which is against periodic trend.
Statement II is false $2 s$-orbital is lower in energy than $2 p$, Aufbau’s principle.
