Why is it expected that 2/10 of the ejected electrons will cone from the n=1 shell, and 8/10 ofthe electron from the n=2 shell?

Answer 1

You don't give enough information about the question to be sure but I assume this is a 10 eletcron system with 2e in the n = 1 and 8e in n = 2. So out of the 10 possibilities, 2 of them are from the n = 1 shell (2/10) and 8 of them are from the n = 2 (8/10).