As the attraction between the nucleus and the electrons is electromagnetic,(see the numbers given by the answer of Michael Faraday) only charges and their interactions with magnetic fields can play a role in what you call "attraction". There is no mass involved.
Mass can play a role as the number of neutrons increases or decreases the mass from the average, isotopes will have a fine structure due to the different charge distributions according to the isotope, and also the different kinematics ( in Bohr model terms) .
Here is a review of how the observations are fitted using quantum mechanical models, not Bohr model.
Measurements of atomic spectra for different isotopes of the same atomic number Z show slight differences—the isotope shifts. This frequency difference of an electronic transition is usually described separately as due to the finite mass of the nucleus—the mass shift—and to the size of the nuclear charge distribution—the volume of field shift. The mass shift is dominating isotope shifts for light atoms, whereas the field shift scales as Z 5 or even up to Z 6 and thus becomes the leading contribution in the case of heavy ones.
Whether the effects can be called "attraction" is doubtful. The review is enlightening.