[Zer0 (OP)]

Hello All!
🙂
🙏

A simple doubt, expecting a simple clarification.

1) Two Hydrogen Atoms can Bond with each other.
👍
But then How is it that the Nucleus Attraction is more powerful than the Electron Repulsion?
🤔

2) Molecular Bonds Vibrate.
👍
All by themselves, like Nucleus keeps them attached, while Electron Field is trying to push them apart?
Like No external source of Power or Energy is required to attain the Vibrations?
🤔

3) Perpetual Motion Machines Do Not Exist.
(Impossible - Laws of Thermodynamics)
👍
So, the Molecular Bonds Vibration is simply Perpetual Motion in an Unperturbed System?
🤔
Molecular Vibrations Cannot be considered as P.M. Machines, Right?




P.S. - I'm a level lower than Novice in Chemistry.
Level - Dum Bum!
🤭
Please could someone/anyone answer the above in KISS Format.
(Keep It Simple Silly)
Thank You!
😊

[Janus]

Your understanding of molecular bonds is wrong. The Nuclei of the atoms are not involved at all. Each hydrogen atom has one electron, which leaves the shell 1 electron shy of being full. Electron shells, when they can, try to fill up.  By pairing up in a molecule, the hydrogen atoms "share" their electrons, filling each others shell.
And even if there was a repulsion/attraction thing going on, that doesn't mean vibration. The system would just settle into a balanced state*

* Though it must be kept in mind that at this scale, we are dealing with a system that is bound by the rules of quantum mechanics, so you really can't apply classical physics ideas to it.

[Bored chemist]

Interestingly, while the OP's grasp of how orbitals work is  in need of help, the actual point is correct.
If you have a hydrogen molecule, the two atoms will always be vibrating.

https://en.wikipedia.org/wiki/Zero-point_energy

However, it doesn't break the conservation laws because you can't do anything with that movement/
You can't bring them to a stop and extract the energy from them.

[evan_au]

But then How is it that the Nucleus Attraction is more powerful than the Electron Repulsion?

The Hydrogen electron and the nucleus have equal and opposite electrical charges, so the atom is electrically neutral, overall.
- The two atoms won't attract or repel each other due to electrostatic charge.

However, you could imagine an electron as being like a little magnet, with a North and South pole
- When you put two magnets together, they will attract each other if you put the North pole of one next to the South pole of the other
- For this reason, electrons like to pair up
- So if you put Hydrogen atoms close together, the electrons of two hydrogen atoms will pair up
- This forms a "single bond" between the two atoms to form a H₂ Hydrogen molecule, because they share 1 pair of electrons

Other atoms can form additional bonds:
- Oxygen atoms can share 2 pairs of electrons, forming the "double bond" in an O₂ oxygen molecule
- Nitrogen atoms can share 3 pairs of electrons, forming a "triple bond"  in an N₂ oxygen molecule

[Zer0 (OP)]

🙄

WooW!
I got Janus & B.C. & Evan respond back to back.
I feel Blessed!
😇
(String of Pearls)

Thank You All of You!
🙏

Okay.
So, here's what i Understand now.

1) Hydrogen Atoms form Covalent Bonds.

2) There is a Possible Attraction between the Electrons, which is say due to the Empty available seat for an Extra Electron in s1 orbit.

3) Hence if Hydrogen Atoms come close, they tend to Attach to each other & Covalently Bond making a Hydrogen Molecule.

4) The Mass of the Nucleus has no role in Attraction of Hydrogen Atoms due to Gravity, as Classical Physics is Not Applicable at Quantum Scales.

5) Once Covalently Bonded, the Hydrogen Atoms do vibrate Slightly.

6) Vibrations are due to Force Field attractions & repulsions of the Protons & Electrons, pushing & pulling on each other.

(Could You Please Correct me on the Above six points Please)

& Here's the Final Original Doubt i had...

7) Thou covalent molecular bond of hydrogen atoms do vibrate Slightly, it's simply Perpetual Motion in an Unperturbed System.

But it just CanNot be asserted to be a Perpetual Motion Machine.

Bcoz the Moment one tries to take work/force/energy out of the it...
Thence it does Not remain an Unperturbed System...Hence Not Possible.
(Please Correct me)


P.S. - i was a bit Confused on the location of the Op while creating it.
Coz it had to do with perpetual motion, i thought the Physics section would be Right.
But Ideally, I'm clear bout Perpetual Motion.
👍
What was doubtful is, if the Hydrogen Molecule is left Undisturbed for Centuries, would it still just keep Vibrating?
🤔
If it's in Space, devoid of Any Force Fields, Vibrations would persist for Thousands of years?
🤔
Surely, on Earth...Vibrations might be coming to a halt.
Like dissipating slowly Right?
They do Not just go on Forever on Earth atleast?
So, Gravitational field, or EM field would interrupt & affect the hydrogen molecule?
& Finally...is there some sorta Energy radiated from that bond inorder to stabilize & stop vibrations?
(Thanks All for your Time)
😊

[evan_au]

4) The Mass of the Nucleus has no role...
5) Once Covalently Bonded, the Hydrogen Atoms do vibrate Slightly.

One simple model of a molecule is to imagine all the atoms joined together with little springs.
- If the atoms get too far apart, the electrons tend to pull them back together
- If the atoms get too close together, the nuclei tend to push them apart
- Each atom has a mass: essentially the mass of the nucleus (since the electrons don't weigh much by comparison)
- Each spring has a length: This is the average bond length, which you can find in chemistry books
- Each spring has a "springiness": how tight or loose it is

If you model a Hydrogen molecule this way: Two masses with a spring in between forms a Simple Harmonic Oscillator.
- It will vibrate in and out at a certain frequency
- In Classical physics, the amplitude of this vibration can take on any value (including zero)
- In the Quantum world, the amplitude of vibration can only take on specific values (which in some systems, may not include zero)
- You can measure these vibrations with infra-red spectroscopy (the energy of the vibrations tends to be in the infra-red part of the spectrum)

In Hydrogen gas at thermal equilibrium, lots of these Hydrogen molecules are travelling in random directions at random speeds, vibrating in and out, and spinning around in random directions.
- They frequently bump into other Hydrogen molecules, or the walls of the container, which will bounce off each other in a different direction with a different random vibration and spin.
- This system of Hydrogen atoms bumping around in random directions will continue as long as the conditions remain unchanged
- This system has maximum entropy, so you can't get it to do work
- It is not a perpetual motion machine, because you cannot extract any energy from it
- you would need an external source of different temperature or different pressure to get it to perform "useful" work.

PS: If you try to model a protein with thousands of atoms and springs, it is a chaotic, wobbly monstrosity, which is why working out how enzymes function requires enormously large supercomputers.

[yor_on]

It's a interesting question.

Don't we need to add superpositions and indeterminacy to it?

at least indeterminacy, but then you have superpositions too.

[evan_au]

EM field would interrupt & affect the hydrogen molecule?

If you hit a hydrogen with a sufficiently energetic photon (in the UV range of the spectrum), you can disrupt it.

You can measure these vibrations with infra-red spectroscopy

Correction: I found out today that a symmetric diatomic molecule like hydrogen or nitrogen does not show up in infra-red spectroscopy, as the molecule needs to have an overall electrical field in order to interact strongly with photons (electromagnetic radiation).

So asymmetric molecules like carbon monoxide (CO) or water (H₂O) do show up in infra-red spectroscopy, but molecular hydrogen does not.

You can measure the vibration of symmetrical molecules like Hydrogen using Raman spectroscopy which measures photons bouncing off the molecule (this uses a laser to generate monochromatic photons, and measures the Doppler shift of the interacting photons).

I guess that's why astronomers have so much difficulty measuring the concentration of molecular hydrogen in interstellar space...

See: https://en.wikipedia.org/wiki/Infrared_spectroscopy#Theory
https://en.wikipedia.org/wiki/Raman_spectroscopy

[Bored chemist]

- In the Quantum world, the amplitude of vibration can only take on specific values (which in some systems, may not include zero)

Don't we need to add superpositions and indeterminacy to it?

Once you add the uncertainty principle to the idea you realise that all molecules must vibrate i.e the amplitude can not include zero.
Because, if it did, the molecules would have exactly defined locations (WRT eachother) and that's forbidden.

[chiralSPO]

Your understanding of molecular bonds is wrong. The Nuclei of the atoms are not involved at all.

Sorry Janus, I think you might need to brush up on your understanding of bonding theory. The nuclei are very much involved! (you won't find collections of electrons forming molecules without them. The bond is effectively a result of the electrons being attracted to both nuclei.

For H₂ (the simple case), we can think of two individual protons that are magically being held near each other (say an Ångstrom apart) in space. Because they are both positive there will be a strong repulsive force acting on them, and no other forces to balance out (the "molecule" will explode into two(H⁺)ions!)

If we add an electron to the system, the most energetically favorable region for it to be in is between the two protons (H nuclei). Now in addition to the repulsion between them, each proton is also experiencing an attractive force to the negatively charged electron between them (H₂⁺ has been observed and can be generated, and is pseudo-stable). If you add another electron to the system, the most favorable region is still between the two protons, but it's a little more spread out because of the other electron. Both protons now have two negatively charged particles pulling them toward the center of the molecule, and only one positively charged particle pushing them away, so this is a very stable configuration (molecular H₂). If another electron is added, now the middle of the molecule is less favorable than the periphery (because the middle is already crowded with electrons). Now, there are added forces pushing the molecule apart: the electron on the periphery is pulling harder on the proton closer to it than the one further away, resulting in a net force separating the protons, and the electron itself is repelled from the two electrons in the middle. (H₂^– has been detected and is pseudo stable. Adding that last electron though, only intensifies the repulsion, and the molecule explodes into two hydride ions (H^–)!

So the nuclei are quite important to bonding. (this is also why each element has different chemistry—the electrons are all the same, its the nuclei that changes the electronic structure!)