The energy change for an electronic transition in a one-electron atom or ion (H,He⁺,Li²⁺,etc.)from n_initial to n_final is given by ,where Z is the atomic number. Which one of the following species will have the longest wavelength emission line for the transition between the n_initial = 2 and n_final = 1 levels?

Question

Quizplus · Accepted Answer

The energy change for the transition is inversely proportional to the wavelength of the emitted photon. Therefore, we need to find the species with the smallest value of Z, as it will result in the greatest wavelength (lowest frequency) of electromagnetic radiation. From the provided options, H has the smallest Z, and thus it will have the longest wavelength emission line for the transition between the n_initial = 2 and n_final = 1 levels.

The Energy Change for an Electronic Transition in a One-Electron