Core Atomic
Structure: Electronic Structure
Slide 29 of 44
On the discreteness of energy levels
Take the example of a ball rolling down a
ramp.
–Energy change is continuous and smooth.
–What that means is that the potential energy of
the ball at the top of the ramp is the maximum and at the bottom is zero.
–During its journey, the ball’s potential energy has
had every possible value between the maximum and zero—it decreases
continuously.
Now let’s take one rolling down a
flight of stairs of the same height and at the same altitude.
–Here potential energy changes by fixed amount,
which is dictated by the height of each step.
–We say the energy change in this case is discrete because every drop from one step to another is accompanied by a loss of a fixed amount of potential energy.
So it is with energy changes accompanying
electronic transitions.
That’s why energy levels are
said to be quantized.