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atoms don't touch (lemmy.blahaj.zone)

submitted 2 months ago by [email protected] to c/[email protected]

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[–] [email protected] 60 points 2 months ago* (last edited 2 months ago) (9 children)

I like the imagery of the last post because it was tapping into the idea of waves and how sub-atomic particles behave like waves.

However, erm actually 🤓 ...

you pet your dog and the electron-orbitals of your skin overlap with the electron-orbitals of his fur

No, they don't overlap. Electrons are negatively charged, and like repels like. The orbitals will repel each other. This repulsion is the reason why you can feel the fur.

Edit: I'm getting nay-sayers that reckon they do. Please provide a reference that explains inter-molecular orbitals that cause bonding for a hand touching fur. The only thing I can think of this happening is for transition states. This would require a chemical reaction. I don't think we categorise "touch" under "requiring a chemical reaction".

Because the structure of the transition state is a first-order saddle point along a potential energy surface, the population of species in a reaction that are at the transition state is negligible. Since being at a saddle point along the potential energy surface means that a force is acting along the bonds to the molecule, there will always be a lower energy structure that the transition state can decompose into. This is sometimes expressed by stating that the transition state has a fleeting existence, with species only maintaining the transition state structure for the time-scale of vibrations of chemical bonds (femtoseconds).

Source: https://en.wikipedia.org/wiki/Transition_state

[–] [email protected] 31 points 2 months ago (6 children)

To um actually your um actually, I think orbitals do overlap, isn't that the very concept of atomic bonding and interaction? There's a Wikipedia article but it's way beyond me. Shame we're not in [email protected], there's usually a few experts hanging round their to correct me!

[–] [email protected] 16 points 2 months ago (5 children)

It was far long ago when I learned these stuff, but I recall that orbitals is more about probability to exist at certain points. So orbitals are more "diffuse" and "fuzzy": there is a probability of an electron to exist 5m away from its nuclei, just the probability is astronomically low. Hence, there is no concept of concrete "touch" at this level.

[–] [email protected] 3 points 2 months ago

Orbitals are actually an approximation, which is what part of the confusion is. The exact math is beyond me, but the idea is that the orbitals represent the most likely place for an electron to be, not the only place. Lots of probability involved, including with how electrons react with each other. Chemical reactions that do happen are just the most likely event, but when you atom by atom things can get really weird. At that scale electron don’t really obey classical physics (which is what intuition usually expects). As a more concrete example, if you take a chemistry class, you probably learn that electrons like to group in pairs of two, which is weird if you think about two negative charges grouping together, but (once a gain with math that I don’t claim to understand) quantum physics does explain this (because of electron “spins” which do not spin like in a classical physics sense) even though it is not intuitive from classical mechanics. Similarly orbital rules break down at some points, such as carbon able to to have 4 bonds (the s and p orbital have very similar energy levels if I remember the chemistry right), which you can’t get from the simplified orbitals.

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