It is relatively easy to strip the outer elections from a heavy atom like that of uranium (which then becomes a uranium ion), but it is very difficult to remove the inner electrons. Why do you suppose this is so?
Solution 18E First of all the distance from the nucleus to the outer electron of a heavy atom is much more compared to the separation between the inner electron of the same atom. Now, we know that the electrostatic force decreases as the square of the distance as distance increases. So for the outer electron, the force is much less compared to the inner electron. Also, the outer electron will experience the attraction due to the positive charge of the proton of the nucleus and the repulsive force of the other electron which are in between the outer electron and nucleus. But for inner electrons there are no negative charges in between nucleus and electron hence only force that will act is the attractive force due to proton. Because of the above reason, the force by the proton to the outer electron is much less compared to the force to the inner electron. Hence it is easier to remove outer electron than an inner electron.