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I have encountered a question from a science contest test that has me stumped. I contend that there is not enough information. The Question: How much energy is required to remove the last electron from the Boron+4 ion? That is it! The answer key says the answer is 321 ev. Without knowing the distance between the electron and the Nucleus I can not see a solution. Any Ideas?

It is quite simple. Boron +4 has a hydrogen like electronic structure because there is only one electron. So you can do the same calculation as for a hydrogen atom but with a different charge on the nucleus.


Yup. What they did not say was that the system was in its lowest energy state, but you can usually assume that sort of thing. Just multiply the Rydberg (the ionization energy of Hydrogen) by 25 to get the ionization energy for Boron...

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