IMathAS-libretexts

the absorption line spectrum of magnesium

Atomic absorption spectra, such as the one shown here for magnesium, contain distinct lines. What is the cause of these lines?

each line corresponds to a specific energy level in an element
specific wavelengths absorbed correspond to differences between electron energy levels
absorption of photons causes specific orbitals to change energy
emitted photons correspond to differences between electron energy levels
the energies of absorbed photons correspond to differences between proton energy levels.