1. The problem statement, all variables and given/known data a) Consider a hydrogenic atom consisting of a carbon-12 nucleus and a single electron. What is the wavelength of the photon emitted when this atom drops from n = 5 to the n = 2 state? b) According to the Bohr theory, what is the distance between the electron and the nucleus in the n = 2 state of the hydrogenic carbon-12 atom? 2. Relevant equations [itex]r_n = n^2 \times a_0[/itex] where [itex]a_0[/itex] is the bohr radius 3. The attempt at a solution I found the answer to part A no problem, but b is giving me trouble. I know that the equation for the radius for excited states is for a hydrogen atom. WIth a carbon nucleus I expect it to be much smaller that the bohr radius, but I can't figure out how to account for the change in nucleus size. Any ideas?