This image shows a ladder in a well. There are 7 rungs on the ladder with the top rung on the same level as the top of the well. There is a particle indicated as p in the bottom of this well, not on the lowest rung of the ladder. This p represents a proton. An electron, represented by the letter e, is shown on the 5th rung of the ladder, two rungs down from the top of the ladder.