What happens when hydrogen gas atoms absorb photons with matching energy differences?

When hydrogen gas atoms absorb photons with energy that matches the energy difference between two of their electron energy levels, specific frequencies of light are indeed absorbed. This absorption occurs because the energy of the incoming photon corresponds to the energy required to move an electron from a lower energy level to a higher energy level. Consequently, these particular frequencies of light are effectively removed from the spectrum of light that passes through the atomic gas.

This phenomenon is fundamental to understanding atomic spectra. When the hydrogen gas is illuminated by a continuous spectrum of light (such as from a white light source), the specific frequencies absorbed by the hydrogen atoms result in dark lines in what would otherwise be a complete spectrum. These dark lines correspond to the wavelengths of light that have been absorbed by the hydrogen atoms, matching the specific energy transitions of the electrons.

Thus, the correct understanding of this process is the absorption of photons leading to the removal of specific frequencies from the continuous spectrum observed.