In an IR spectra the X axis is wavenumber of the IR radiation which is another way to describe the of the radiation. There is a direct correlation between wavenumber and energy, thus the higher the wave number the the energy The Y axis is which is a measure of the light that makes it through the sample to the detector. Light that does not make it through the sample to the detector is by a functional group in the molecule and converted to

Energy, more.

Explanation:

wavenumbers are directly proportional to energy and frequency of the radiation means that if one increases the other automatically increases whereas one decreases the other is also decreases. If the wavenumber increases, the energy of radiation is also increases while on the other hand, if the wavenumber decreases the frequency and energy of radiation is also decreases.

the atomic mass is the bottom number on the element.

-steel jelly