Quantum mechanics, which “rules” the behavior of matter from the tiniest dimensions, rarely comes up in casual conversation, even if it hits the news about superspeed quantum computing and entanglement. More fundamentally, “QM” tells us why atoms don’t “run down” to negative electrons just sitting on the positive nuclei that attract them.
When electrical charges race around each other, they radiate away electromagnetic radiation and lose energy; it’s the way we generate radio and TV signals. Yet, atoms can have zipping electrons even for billions of years?
Ah, an early “quantum mechanic,” Werner Heisenberg, formulated the uncertainty principle. Skipping over some beautiful math,a simple view is that, at these tiny, fundamental scales of distance in atoms, both position and momentum (velocity times mass) are mutually uncertain. Pin down one of them and the other is more uncertain. If the electron would slow down, its position would really jump, negating its slowing down. If it settles into a small area, its speed gets high, so it “escapes".
Electrons elegantly compromise, ending up in stable clouds as states, roughly viewed as orbits. There is a minimum energy or ground state, where electrons still zip around.
This has been an outreach activity of the Las Cruces Academy, viewable at GreatSchools.org.
Source: My career in chemistry and physics
