Do atoms absorb the same amount of light? I'm currently working on a project on my own where I'm interested in finding information about an object based on a spectrum. Namely, I want to use the spectrum that I input into my program to be able to analyze what atoms are present in the analyzed object. (I know this is probably hard but it's a fun project). However, when I started to work on this my question arose:
Do atoms that are exposed to the same amount of light absorb the same amount as well? (Albeit different frequencies).
So, when the atoms are exposed to light (uniform over the EM spectrum), will two atoms that absorb different frequencies absorb the same amount of light? And if so, one could infer that the less light of a specific frequency that we can find, (the less compared to the maximum that would be emitted at that frequency) the more there is of the element that absorbs this specific frequency? (Though it would probably be useful to look at more than one "black line" in the spectrum)
 A: The amount of light is not a precisely defined quantity here. For your purposes it may be safe to assume that each atom may absorb only one photon, however these photons would have different frequencies. The number of photons of different frequencies absorbed is then proportional to the number of atoms absorbing this frequency. Thus, distinct peaks in a spectrum would correspond to different types of atoms, whereas the intensity of the peaks (proportional to their height or their area) would correspond to the number of atoms of each type. However, the above analysis of a spectrum is true only for the atoms in a gaesous phase - the absorption spectrum of a liquid or solid is rather different from the spectra of the atoms, of which it is made.
A: 
Do atoms that are exposed to the same amount of light absorb the same
amount as well?

The question is a little fuzzy, so let's try an be more concise.
Take sodium ($\text{Na}$), famous for its strong, yellow doublet emission line.
In identical conditions all sodium atoms emit the same intensity of that yellow doublet (and its other weaker lines)
A constant gas flame of a given sodium concentration would thus emit yellow light, the intensity depending only on the sodium concentration. Similarly, such a flame would also absorb the same amount of light made up of those frequencies (the principle of Atomic Absorption Spectrometry), depending only on sodium concentration.
A: Different materials will absorb different amounts.  You cannot rely on two materials to absorb the same number of watts per mole, or anything like that.
The ultimate case study would be the white paint used to coat roofs and charcoal.  They both obviously do have an absorption spectra, in different frequencies.  However, it is trivial to show that the white paint fundamentally absorbs less, which is why we use it on roofs in the first place!
