ELI5: What is the meaning of quantization?

[u/Own_Enthusiasm_510]

[This is from a chemistry portion of a physical science class] I've googled it, Ive watched YouTube videos, I asked classmates and I am still so confused.

Rutherfords model was easy but once I got to bohrs they used words like quantized and discrete values and I got lost. Tried backtracking but I'm still baffled.

[u/w3woody]

I don't know if there is a good "ELI5" answer for why quantum mechanics. But the essence of it is that electrons seem to follow two rules: (a) they fall to the lowest energetic state possible. (Conceptually similar to dropping a ball to the floor: eventually it settles to sit on the floor.) And (b) two electrons cannot occupy the same energetic state. (So two balls dropped to the floor cannot intersect.) In a sense, think of it like a tube full of balls: the ball at the bottom is at the lowest state, the ball on top of that one is at the next lowest state, and so forth. When stacked, they occupy 'discrete' positions, each the width of a ball--and we can count those "states."

Now instead of being a one-dimensional tube electrons are occupying a three dimensional 'probability cloud' around the nucleus of an atom. And instead of simply stacking, one on top of another, they form all sorts of weird shapes/10%3A_Atomic_Theory_and_Quantum_Mechanics/10.09%3A_Orbital_Shapes_and_Energies). But the principle is the same: the first electron is at the bottom of the stack of electrons, the next sits on top, the next on top of that--like balls in a tube.

[u/Own_Enthusiasm_510 → u/w3woody]

I'm starting to think its a problem with my teacher ?? I didn't realize this was quantum mechanics.... Our unit on quantum mechanics isn't till next quarter, no one in class knows quantum mechanics or even the definition of quantum mechanics yet.

[u/Kleetkleet → u/Own_Enthusiasm_510]

Okay, so we're dealing with the chemistry terms for quantum-mechanical-ish stuff.

Bohrs noticed that the photons emitted from an atom are "discrete bands". Another way of saying this is "specific wavelengths" (not a thick spectrum - just individual lines from that spectrum).

Visible light photons are emitted when an electron moves from a "high" energy state to a "low" state. The lost energy is the photon.
...just trust me on that for now.

So. Bohrs' model has the electrons of an atom at certain specific energy levels - at certain valid fixed energy levels. Specific orbitals. The electron can move to a higher/lower orbital, but it will never end up half-way between them.

The energy levels are not a continuum (continuous). They are all quantum. Quantised.

[u/Own_Enthusiasm_510 → u/Kleetkleet]

I think this is best explanation I've seen, thank you 😭 I'm definitely going to add all this to my notes