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?
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).
To understand why it is expected that 2/10 of the ejected electrons will come from the n=1 shell, and 8/10 of the electrons will come from the n=2 shell, we need to consider the concept of electron configuration and energy levels in an atom.
Electrons in an atom are arranged in specific energy levels, also known as shells or orbitals. The energy levels are labeled with principal quantum numbers represented by n=1, n=2, n=3, and so on. The smaller the value of n, the closer the energy level is to the nucleus of the atom.
Now, when an atom absorbs energy, such as in a process called photoionization, electrons can be ejected from their current energy levels. However, not all electrons are equally likely to be ejected since the energy levels have different probabilities of occupation.
According to the Aufbau principle, the lowest energy levels (n=1) are filled first before moving to higher energy levels (n=2, n=3, etc.). Each energy level can accommodate a specific number of electrons based on the maximum number of electrons allowed in each orbital.
In the case of the question, 2/10 of the ejected electrons are expected to come from the n=1 shell, and 8/10 from the n=2 shell. This expectation is based on the probability of finding electrons in these energy levels.
The probability is determined by the electron configuration of the atom. For example, in the case of hydrogen, which has one electron, it occupies the n=1 energy level. Therefore, if it absorbs enough energy to be ejected, it will come from the n=1 shell.
For larger atoms with multiple electrons, the probability is determined by the electron configuration of the atom. As electrons fill up the available energy levels, the lower energy levels tend to have higher occupancy as per the Aufbau principle. This results in a higher probability of finding an ejected electron from the n=1 shell (2/10) compared to the n=2 shell (8/10).
In summary, the expectation that 2/10 of the ejected electrons will come from the n=1 shell and 8/10 from the n=2 shell is based on the electron configuration and energy levels in an atom, where the lower energy levels have higher probability of occupancy according to the Aufbau principle.