## atomic emission vs atomic absorbtion

H-Atom ($E_{n}=-\frac{hR}{n^{2}}$)

Dahriel Aron 3A
Posts: 60
Joined: Fri Sep 25, 2015 3:00 am

### atomic emission vs atomic absorbtion

After watching the videos I am very confused about the difference between atomic emission spectrum and atomic absorption spectrum. My interpretation from the videos was that these 2 ideas were the same concept, although now it has become clear that they have differences between them. I was wondering if anyone could explain the differences between these 2.
Thank you!

Carly Wong 4H
Posts: 7
Joined: Fri Sep 25, 2015 3:00 am

### Re: atomic emission vs atomic absorbtion

Atomic absorption refers to when electromagnetic radiation (or light) is ABSORBED by an element causing the electrons within the element to become excited and increase their energy level. However, in order for these electrons to reach an energy level, a specific wavelength (or frequency) of light must shine upon the element. An atomic absorption spectrum is a series of lines that represent the wavelengths it takes to jump from level to level.
Atomic emission refers to the light or energy that is EMITTED from the element (and recorded by a detector) and is essentially the same wavelengths as the atomic absorption because the energy it takes for the electron to get excited to a higher level is eventually emitted when the electron falls back down to its ground state. Therefore, the atomic emission spectrum shows the same wavelengths (lines) as that of the atomic absorption spectrum.
It is also important to remember that each spectrum is specific to the element.

Chem_Mod
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### Re: atomic emission vs atomic absorbtion

Carly is correct. the energy/frequency/wavelength values are all the same for absorbtion and emission. Physically, the spectral lines are created by emission, when electrons drop from high to low levels. But sometime before that, those electrons had to be promoted from low to high levels (absorbtion)

Juskarun Cheema
Posts: 15
Joined: Fri Sep 25, 2015 3:00 am

### Re: atomic emission vs atomic absorbtion

I am a bit confused on whether the spectrum shows the wavelength or whether it shows the frequency emitted by the gas sample.

Carly Wong 4H
Posts: 7
Joined: Fri Sep 25, 2015 3:00 am

### Re: atomic emission vs atomic absorbtion

Most of the time the atomic emission/absorption spectrums will show wavelength (often measured in nm), but of course wavelength can be converted into frequency using $c=\lambda \nu$