Question

Why do you get essentially the same X-ray emission spectra for elements regardless of their form (i.e. Cd will yield the same characteristic wavelengths whether it is as elemental Cd, CdS (solid) or CdS (gas)?

Answer 1

Characteristic x-rays are emitted from heavy elements when their electrons make transitions between the lower atomic energy levels. The characteristic x-ray emission which is shown as two sharp peaks in the illustration at left occur when vacancies are produced in the n=1 or K-shell of the atom and electrons drop down from above to fill the gap. The x-rays produced by transitions from the n=2 to n=1 levels are called K-alpha x-rays, and those for the n=3→1 transition are called K-beta x-rays. & so the characteristic x ray spectra does not depend upon the substance nature I.e solid or gas. it only depend s upon the electronic structure of the substance used.