Atomic Structure Question 184
Question: The electrons, identified by quantum numbers $ n $ and $ l $ (i) n = 4, $ l $ = 1, (ii) n = 4, $ l $ = 0, (iii) n = 3, $ l $ = 2, and (iv) n =3, $ l $ = 1 can be placed in order of increasing energy, from the lowest to highest, as
Options:
A) (iv) < (ii) < (iii) < (i)
B) (ii) < (iv) < (i) < (iii)
C) (i) < (iii) < (ii) < (iv)
D) (iii) < (i) < (iv) < (ii)
Show Answer
Answer:
Correct Answer: A
Solution:
- The two guiding rules to arrange the various orbitals in the increasing energy are:
(i) Energy of an orbital increases with increase in the value of n+1
(ii) of orbitals having the same value of n+1, the orbital with lower value of n has lower energy.
Thus for the given orbitals, we have
(i) n+1=4+1=5 (ii) n+1=4+0=4
(iii) n+1=3+2=5
(iv) n+1=3+1=4
Hence, the order of increasing energy is (iv) < (ii) < (iii) < (i)
