concept problem, we can determine the possible value of Lx in hydrogen atom? The book of introduction to quantum mechanics told me that The value of Lx can not be determined. I know the concept behind this statement However, when I am practicing, I see one of my question that requires me the determine the possible value of Lx as well as the probability! This is not a homework. How to determine it? It is possible? The book tell me that Lx can be determined! Is there anything that I am missing?