Several excited states of the neon atom are important in the operation of a helium-neon laser. In these excited states, one electron of the neon atom is promoted from the 2p level to a higher energy orbital.

An excited neon atom with a 1s²2s²2p⁵5s¹ electron configuration can emit a photon with a wavelength of 3391 nm as it makes a transition to a lower energy state with a 1s²2s²2p⁵4p¹ electron configuration. Other transitions are also possible. If an excited neon atom with a 1s²2s²2p⁵5s¹electron configuration makes a transition to a lower energy state with a 1s²2s²2p⁵3p¹ electron configuration, it emits a photon with a wavelength of 632.8 nm. Find the wavelength of the photon that would be emitted in a transition from the 1s²2s²2p⁵4p¹ electron configuration to the 1s²2s²2p⁵3p¹ electron configuration. (It should help if you start by drawing an energy-level diagram.)