Trying to understand a reading on Moseley and the X-ray Spectra

1. Feb 20, 2006

UrbanXrisis

I was wondering why Henry Moseley ploted $$\sqrt{f} vs. Z$$ instead of just $$f vs. Z$$. I'm guessing it is because this way, the graph of $$\sqrt{f} vs. Z$$ would be linear? But if it was just $$f vs. Z$$, wouldnt the equation just be exponential?

Also, what is the significance of the L seriese and the K seriese? The K seriese describes the atomic transitions to vacancies in the n=1 shell where the L seriese describes the transition to the n=2 vacancy right? So by Moseley's plot, i see that there is a lower frequency for the K-seriese which means that more energy is released right? But what I really dont understand is why $$b=7.4$$ for the L seriese and $$b=1$$ for the K seriese. This is something my book does not explain. and why (Z-b)?

why where there gaps in Moseley's experiment such that argon fell into Z=18? and I dont understand what exactly Auger did to help this out. All i got out of the book was that there is a third electon? I think the elements that Auger used were Cu and Al to help out Moseley's expirments?

2. Feb 24, 2006

Staff: Mentor

Quick response to the first question. The frequency of the X-ray (or photon in general) is proportional to Z2 in the hydrogen atom, or for K electrons. The significance of the K and L shells (principal quantum numbers, n = 1 and 2, respectively) have to do with the energies of the transitions to those orbits. K series X-rays should have higher frequency/shorter wavelength than L-series X-rays.

The K electrons are in the first shell and thus exposed to the full nuclear charge. The L electrons are shielded by the K electrons and partially by other L-electrons, hence the correction on Z.

More later.