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Question: Answered & Verified by Expert
If the given four electronic configurations.
(i) $n=4, l=1$
(ii) $n=4, l=0$
(iii) $n=3, l=2$
(iv) $n=3, l=1$
are arranged in order of increasing energy, then the order will be
ChemistryStructure of AtomWBJEEWBJEE 2017
Options:
  • A (iv) $ < $ (ii) $ < $ (iii) $ < $ (i)
  • B (ii) $ < ($ iv $) < (i) < ($ iii $)$
  • C (i) $ < $ (iii) $ < $ (ii) $ < $ (iv)
  • D (iii) $ < $ (i) $ < $ (iv) $ < $ (ii)
Solution:
2918 Upvotes Verified Answer
The correct answer is: (iv) $ < $ (ii) $ < $ (iii) $ < $ (i)
According to $(n+l)$ rule;
(i) More be the sum of $(n+l)$ value, more be the energy.
(ii) For same value of sum, more be the value of $n$, more be the energy.
For
(i) $n+l \rightarrow 4+1=5$
(ii) $n+l \rightarrow 4+0=4$
(iii) $n+l \rightarrow 3+2=5$
(iv) $n+l \rightarrow 3+1=4$
Hence, order of energy will be
(iv) $ < $ (ii) $ < $ (iii) $ < $ (i)

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