Can atoms not notice each other?

[icakeov]

This might be an odd question, or perhaps it has an obvious answer. Atoms can attract or repel one another, or they can form a bond, but is there such a thing where atoms or molecules would pass by each other and not "notice" one another, or better, not become reactive in any way, basically, no bond, no attraction, no repulsion.
I'm imagining the answer is no, but thought I'd check in to make sure.
Any feedback appreciated.

 

[DaveC426913]

Look up the noble gases, keyword: inert.

 

[DrClaude]

Look up the noble gases, keyword: inert.

That means that they do not form chemical bonds (with a few exceptions). It does not mean that the atoms do not interact with each other.

 

[DrClaude]

This might be an odd question, or perhaps it has an obvious answer. Atoms can attract or repel one another, or they can form a bond, but is there such a thing where atoms or molecules would pass by each other and not "notice" one another, or better, not become reactive in any way, basically, no bond, no attraction, no repulsion.
I'm imagining the answer is no, but thought I'd check in to make sure.
Any feedback appreciated.

Of course, it depends on how close they come to each other, but "no" is the answer.

 

[DaveC426913]

That means that they do not form chemical bonds (with a few exceptions). It does not mean that the atoms do not interact with each other.

1. True, but depending on how you interpret the OP's question, that may be what they are asking for.
2. Nudging the OP to do some reading will help them refine their own understanding and perhaps refine the question.

 

[Vanadium 50]

depending on how you interpret the OP's question,

no bond, no attraction, no repulsion.

Seems pretty clear to me.

Two helium atoms will not bind. They will have a weak induced dipole-induced dipole attraction, and of course if they smack into each other they will elastically scatter. So I think the question has a well-defined answer: "no".

 

[icakeov]

Thank you everyone for your responses! Super helpful.

Yes, inert gases are a good example, but only in the domain of chemical reactions, whereas I am realizing my question has to include any physical reactions or "responses", which is what I would have meant by "not notice each other".

Perhaps one way to have asked the question is whether there is any atom or molecule that behaves like a neutrino around other atoms, and the answer, I think it is safe to conclude, is clearly no. If any atom or compound comes close to another, it will have to "interact" with it as if the other entity is a physical object, perhaps not wanting to react with it, such as inert gases, but for sure it won't be able to "ignore" or "avoid" its existence in the inert gas's path, causing some effect.

And the question is specifically about them passing near each other, rather than direct intersection, and that's the zone where even with inertness, there are weak forces that "do something" even if it is a small effect.

Thank you again!

 

[DaveC426913]

In that case, for further reading, you might be interested in bosons and fermions.

All matter is fermionic, it obeys the Pauli exclusion principle, and occupies space, so you can't have two in the same place. You can fill a box full of fermions until you can't fit any more in.

Other particles, such as light, are bosonic; they do not obey PEP, which mans you can put as many of them in a box as you want and there will always be room for more - they don't exclude each other. Loosely speaking, they don't really interact - for the most part, they'll happily pass right through each other.

 

[icakeov]

Perfect! Thank you!

 

[DrClaude]

In that case, for further reading, you might be interested in bosons and fermions.

All matter is fermionic, it obeys the Pauli exclusion principle, and occupies space, so you can't have two in the same place. You can fill a box full of fermions until you can't fit any more in.

Other particles, such as light, are bosonic; they do not obey PEP, which mans you can put as many of them in a box as you want and there will always be room for more - they don't exclude each other. Loosely speaking, they don't really interact - for the most part, they'll happily pass right through each other.

Composite particles such as atoms can be either bosons or fermions. Also, neutrinos are fermions, but still don't interact much with other matter.

The main point about the original question is that atoms are composites made up of charged particles, which means that they will interact with each other no matter what.

 

[snorkack]

Composite particles such as atoms can be either bosons or fermions.

Indeed. A helium atom could be He-4 (boson) or He-3 (fermion).
He-3 atoms have an extra repulsion because they cannot occupy the same state, but He-4 atoms still repel.

Also, neutrinos are fermions, but still don't interact much with other matter.

It is difficult to measure neutrino-neutrino repulsion, but it must exist. How does a Fermi sea of neutrinos look like?

The main point about the original question is that atoms are composites made up of charged particles, which means that they will interact with each other no matter what.

Indeed. For example, pions are bosons, yet charged pions have a charge. It follows that if you had a Li atom with three negative pions, they can all occupy 1s state (because they are bosons) but should still experience electric repulsion (because they are charged).