Question

How many minimum H-atoms are required to observe the maximum number of distinct spectral lines where an electron jumps from O shell to K shell?
A. 3
B. 5
C. 6
D. 4

Answer 1

Hint: Hydrogen atom consists of only one electron. But the emission spectrum consists of several lines. The various possibilities by which an electron is excited to a higher energy level s known electronic transitions. The series of spectral lines in the emission spectrum can be classified as five series. K shell has the principal quantum number \[n = 1\] and the O shell has the principal quantum number \[n = 5\]. It symbolizes that an electron jumps from fifth to first energy level.

Complete answer:
In the question, it is given that an electron jumps from fifth to first energy level. Thus, a total of ten distinct lines are observed in the hydrogen spectrum as four Lyman series, three Balmer series, two Paschen series, and one bracket series.
The possible transitions for an electron jump from O shell to K shell can be written as,
\[O \to N \to M \to L \to K\]
\[O \to N \to L \to K\]
\[O \to N \to K\]
\[O \to M \to K\]
\[O \to L \to K\]
\[O \to K\]
Here, some of them may consider \[O \to M \to L \to K\] as one of the possibilities of spectral lines. But in question, a maximum transition is needed. \[M \to L\] Is a small transition from third to second energy levels. So, it is not considered.
Thus, there are six minimum H-atoms are required to observe a maximum number of distinct spectral lines where an e jumps from O shell to K shell

Hence, option C is the correct option..

Note: Lyman series are produced when an electron jumps from any of the higher levels to the first energy level. Balmer series are produced when an electron jumps from any of the higher levels to the second energy level. Paschen series is produced when an electron jumps from any of the higher levels to the third energy level. Bracket series are produced when an electron jumps from any of the higher levels to the fourth energy level. Pfund series are produced when an electron jumps from any of the higher levels to the fifth energy level.