Research has highlighted difficulties experienced by students when studying quantum physics in introductory courses. In this paper, we present a teaching and learning sequence (TLS) aiming at introducing a quantum model of emission and absorption of radiation and we assess its impact on the students' learning about atomic spectra. The TLS has been designed based on the contributions from physics education research and it was implemented among high school seniors. A detailed description of the TLS is also presented accompanied by a description of how it is implemented. Based on a pre- and post-assessment questionnaire and student interviews, we conclude that students are able to successfully use the models to reason about relevant phenomena.