## Atomic Spectrum and Series

$c=\lambda v$

Dakota_Campbell_1C
Posts: 51
Joined: Fri Sep 28, 2018 12:15 am

### Atomic Spectrum and Series

In the spectrum of atomic hydrogen, several lines are generally classified together as belonging to a series (for example, Balmer series, Lyman series, Paschen series), as shown in Figs. 1.10 and 2.1. What is common to the lines within a series that makes grouping them together logical?

Having trouble conceptually understanding this type of question. Is the answer just the fact that each of the series have a very close range of wavelengths?

Te Jung Yang 4K
Posts: 63
Joined: Fri Sep 28, 2018 12:18 am

### Re: Atomic Spectrum and Series

The common aspect of each of these series is that the energized (excited electron) falls down to the same quantum level (n=X).

For example, the Balmer series is the result of electron transitions from higher levels down to the energy level with principal quantum number 2.

This definition causes the very close range of wavelengths. Since all of the excited electrons fall down to the same energy level in a series, the photons released due to the electron transitions (and hence the wavelengths of the photons released) will be similar. I would recommend looking at a diagram for a better visualization.

Dakota_Campbell_1C
Posts: 51
Joined: Fri Sep 28, 2018 12:15 am

### Re: Atomic Spectrum and Series

Thank You!

Hai-Lin Yeh 1J
Posts: 89
Joined: Fri Sep 28, 2018 12:16 am
Been upvoted: 1 time

### Re: Atomic Spectrum and Series

Wait, can someone elaborate what it means by a close range of wavelengths? These series are different because for the Balmer series, the energized electrons fall down to n=2, whereas the lyman series falls down to n=1 right? Also, in the answer key, it says "in each of these series, the principal quantum number for the lower energy level involved is the same for each absorption line". Can someone clarify this?

megan blatt 2B
Posts: 61
Joined: Fri Sep 28, 2018 12:28 am

### Re: Atomic Spectrum and Series

To clarify a little bit for you, the series are classified based on their similar wavelengths. This means they fall near each other on a light spectrum. The series are differentiated based on the shell that the electrons in those series relax to. So, you are correct when you say that in the Lyman series, the electrons relax from a higher shell to the n=1 shell. In the Balmer series, the electrons relax from a higher level to the n=2 shell and in the Paschen series, the electrons relax from a higher level to the n=3 shell. Also, due to the similar wavelengths in each series, each series also correlates with a certain kind of light. Lyman series is associated with UV light, the Balmer series is associated with visible light and the Paschen series is related to infrared light. As for the answer key saying, "in each of these series, the principal quantum number for the lower energy level involved is the same for each absorption line," this is just saying that each series shares a lower energy level. For example, as I mentioned before, all waves in the Lyman series have a lower energy level of n=1.