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When a certain element is bombarded with high-energy electrons, kα x-rays that have an energy of 2611 ev are emitted. determine the atomic number z of the element. use the bohr model as necessary?

User Kolombo
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1 Answer

7 votes
Use Moseley's Law for Kalpha.

nu = (2.47 x 10^15) (Z - 1)^2

We know that E = h*nu, so...
nu = E / h

substitute, rearrange, etc, you get...

Z = sqrt( (E/h)/(2.47*10^15) ) + 1

Answer yields 18.98 ... ~ 19, hence Potassium, like I wrote earlier in reference to NIST tables.
User Sherwood Botsford
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