Final answer:
The emission spectra and electronic structure of atoms, specifically the hydrogen spectrum, were explained by Niels Bohr's model which proposed that electrons move in circular orbits and transitions between these orbits result in the emission or absorption of light.
Step-by-step explanation:
The theory for the emission spectra and electronic structure of atoms, specifically the hydrogen spectrum, was explained by Niels Bohr. Bohr's model proposed that electrons move in circular orbits around the nucleus and transitions between these orbits result in the emission or absorption of light. The emission spectrum of hydrogen consists of bright lines at specific wavelengths, while the absorption spectrum has dark lines at the same positions. Bohr's model revolutionized the understanding of atoms but could not explain the spectra of heavier elements.