Elements that do not produce X-rays [closed]

I have read that hydrogen does not produce X-rays as the energy difference between its shells is small.

So if this is true what are the elements that do not produce X-rays and how was Moseley able to plot the frequency of the radiation for such elements?

• Is the statement in the quote block yours, or is that quoted from something? – Bill N Apr 19 at 19:26
• It was an answer to a question – Asher2211 Apr 19 at 19:28

• Why do we get frequency of radiation=$0$ for hydrogen when we apply Mosley's formula? – Asher2211 Apr 19 at 20:38
• Moseley’s law is an approximation derived for heavy nuclei. It predicts the transition energy is proportional to $(Z-b)^2$ rather than $Z^2$. The constant $b$ reflects “screening” of the nuclear charge by the inner electrons (note from the link that $b_K \approx 1$ and $b_L\approx 8$). But a neutral hydrogen atom doesn’t have any inner electrons to screen the proton’s charge, so the Moseley approximation is bad. – rob Apr 20 at 0:13