Ok I've had this problem with this last part of this one question. Show that Moseley's Law for Ka radiation may be expressed as sqrt(f)=[sqrt((3/4)*(13.6/h))]*(Z-1) where f is the x-ray frequency and z is the atomic number. (b) Check the agreement of the original 1914 data shown in Figure 9.18 with Moseley's law. Do this by comparing the least-squares slope and intercept of the Ka line in Figure 9.18 to the theoretical slope and intercept predicted by Moseley's law. (c) Is the screened charge seen by the L shell electron equal to Z-1? Now the first two parts were really easy, but I'm not so sure on the last part. The book does say that an electron in the L shell will be partially screened by the one remaining K shell electron and so it 'sees' a nuclear charge of only Z-1. I mean this fact was needed to do the first part of the question, and I kind of understand that since there is one electron in the K shell when a vacancy is left behind that the atomic number would appear to be Z-1. But does this mean that if the K shell is filled the the screened charge seen by the L shell electron is equal to Z-2? Sorry if this is a stupid question, but I'd just like to understand this concept.