why does the rydberg equation work for hydrogen and not helium
Rydberg formula It's important to notice that this formula can be directly applied only to hydrogen-like, also called hydrogenic atoms of chemical elements, i.e. atoms with only one electron being affected by an effective nuclear charge (which is easily estimated). Examples would include He+, Li2+, Be3+ etc., where no other electrons exist in the atom.
Shekhinah This term does not occur in the Bible, and is from rabbinic literature.[2]:148[3][4]
Color Electromagnetic radiation is characterized by its wavelength (or frequency) and its intensity. When the wavelength is within the visible spectrum (the range of wavelengths humans can perceive, approximately from 390 nm to 700 nm), it is known as "visible light".
Stockholm Water Prize 2006: Professor Asit K. Biswas, The Third World Center for Water Management