Rydberg Equation n

[annabel 2A]

When doing problems using the Rydberg Equation, how do you know which energy level is n1 and which is n2?

Sample question -- 6th Edition Chapter 1 #13: Use the Rydberg formula for atomic hydrogen to calculate the wavelength of radiation generated by the transition from n=4 to n=2.

[Sabrina Ryu 3L]

The differing energy levels depends on which series of the electromagnetic spectrum you are using! When the question asks about the visible light spectrum, you are using the Balmer series, where n1 = 2. Otherwise, when asked about the ultraviolet part of the spectrum, you are using the Lyman series, where n1 = 1. For the example problem, the calculated wavelength of light is 4.86 x 10^2 nm, which is in the visible light spectrum (blue). Thus, it is in the Balmer series!