Ionization Energies Calculation

[Integral0]

How do you go about calculating the ionization energies from atoms?
Electron affinities? (KJ/mol)
for example,

"Calculate the change in energy from the first and fourth ionization energies of Be?"

Recently on a test (CHEM AP HIGH SCHOOL), I had a question similar to this on an exam. I got it wrong b/c I believe that bohr's equation only worked for Hydrogen atoms.

E = -2.178 x 10^-18 J (z^2/n^2)

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Please do not include upper level (meaning above the level of an introductory course in chemistry) material that would enable the calcuations. Please include introductory level "ways" to the change in ionization energies.

Thank you

[GCT]

The Bohr's equation only applies to hydrogen atoms. Actually it applies to hydrogen electrons and in this sense it is not directly related to ionization energies. In regards to a standardized equation which applies to all elements giving a quantitative value for ionization energies...I don't believe that this is in scope of high school ap chemistry.

The only equation which I can think of at this moment is that of nuclear effective charge. Which can only give you an idea of the relative values of first, second, third, fourth ionization energies. You are probably leaving out some information here which the test included. You can also use Columb's law, but you need to know the radius of Be.

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