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[–] [email protected] 58 points 3 months ago* (last edited 3 months ago) (3 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 πŸ€“ ...

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 3 months ago (1 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 3 months ago (2 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] 12 points 3 months ago (1 children)

Yeah that's my recollection too. The areas where they are likely to exist overlap, and that's what a bond/interaction is. The trouble with this stuff is that every year you studied it they told you that what you learned last year was a complete simplification and not really representative of what really happens!

[–] [email protected] 8 points 3 months ago (1 children)

The trouble with this stuff is that every year you studied it they told you that what you learned last year was a complete simplification and not really representative of what really happens!

The real trouble is that every single year they tell you that, it's true!

[–] julietOscarEcho 8 points 3 months ago (1 children)

It's models all the way down. We don't have access to some ultimate truth. Rather as you delve deeper the model is able to predict more accurately esoteric corners of reality, and/or more parsimoniously tie together the empirical facts we know.

"what really happens" is for dogmatists. If your model has no blind spots you probably haven't been imaginative enough.

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

Yeah. That's why it's true every year πŸ˜‰

[–] [email protected] 4 points 3 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 β€œspins” 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.

[–] AngryPancake 13 points 3 months ago

I'll write an explanation here, but I'll try to answer all questions from the thread. Also quantum mechanics is complicated, so sorry for the long text.

Electron orbitals are weird and complicated, for hydrogen we can solve them analytically and depending on the quantum number of the energy levels we are looking at, they take the forms as in the picture on Wikipedia:

https://upload.wikimedia.org/wikipedia/commons/thumb/e/e7/Hydrogen_Density_Plots.png/1280px-Hydrogen_Density_Plots.png

Now whatever energy levels and quantum numbers are, what we are seeing is the probability of the location of the outer most electron (ok hydrogen only has one).

To understand bonds, we don't really need the picture of orbitals, but what's important is understanding that electrons occupy shells. A certain number of atoms can fit into a shell and when it's full, the electrons start a new shell. It gets complicated quickly with more electrons, however in the simpler case, a shell can fit 2n^2 electrons, where n is the shell number. So for n=1, a maximum of 2 electrons can fit, for n=2, a maximum of 8 electrons can fit.

Shells want to be filled, so that leads to two possible bond types. If an atom with a free electron comes close to an atom that has a free spot for an electron, the electron can hop over to the other atom, at which point we have an ionic bond (the atom that loses the electron loses one electric charge and is thus positively charged, the other atoms gains an electric charge and is then negatively charged, so they want to be together).

Another option is covalent bonding, where instead of an electron jumping to another atom, the atoms actually share the electron.

Now do orbitals overlap? I wouldn't give that question a yes or no, because, at that level, we can't really separate atoms anymore. When the atoms are far apart we can draw separate orbitals for both, but when they get together, new orbitals form that is the solution of the electronic configuration of the new molecule we just created. It's more like the orbitals that we have get deformed into new orbitals.

[–] [email protected] 4 points 3 months ago

Is it electrons travelling in your brain that made you think that?

I have read about solipsism but I refuse to believe information I gathered from materials made from quarks and gluons, transported to my body via photons