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MitsuruYamada
New Contributor III

Re: A Chemical Thought Experiment: If two Hydrogen atoms were to collide, then a Hydrogen molecule will be formed?

The discussion is stopping.  It is stagnant.

Let us change our view on the subject, Sirs.

For example, let us consider the states of the two electrons which are involved in the hydrogen molecule.  My naive view is as follows.

Usual oil like salad oil and water do not mix with each other.  Even if you are going to shake the French dressing bottle many times in order to get a delicious sauce, oil portion and water portion will separate out soon.  They dislike each other.  So they separate out even in the common vessle.

For a pint of water, a pint of oil is a substance to reject to coexist in the same region of space.  Much the same way, for an electron, the other electron is an entity to reject to coexist in space.  As you know, the two eletrons are repelling each other through the Coulomb electric force.

When talking about the electrons involved in an atom or in a milecule, people often use the word "electron cloud."  But is it really correct to use such a word "electron cloud" for describing a group of electrons?

Restricting the discussion to hydrogen molecule, in a sense, one electron may be regarded to be a water, the other electron the oil.  Even if each may be expressed by the word "cloud", they can never mix each other.  Can we call suh an unstable aggregate simply as a "cloud"?

It is not just the matter of terminology whether to use the word "cloud", but an inquiry as to how should we image the motion of the two electrons.  The two electrons are attracted by the two protons and at the same time are repelling each other.  How are they moving?  How can they work to make the way of existence of the hydrogen molecule stable?

If the matter is about a hydrogen atom, then one can understand the description of the electron distribution by the word "electron cloud" easily.  The concept of "one-electron-cloud" does not involve any difficulty.  On the contarry, the concept of "many-electron-cloud" sounds something odd.  Because it is not a calm stable distribution of the "mists", but an aggregate of many kinds of oil and many kinds of water all of which cannot mix with anyother and are forced to coexist in the same region of space.  In other words, it may be said to be a kind of "explosive vapor."

How do you think, Sirs?

Thank you for your time

Sincerely

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gmbodner
New Contributor II

Re: A Chemical Thought Experiment: If two Hydrogen atoms were to collide, then a Hydrogen molecule will be formed?

This is a classic problem that can be understood in terms of a simple model. Assume that each hydrogen atom contains a proton and an electron. (Let's not worry about whether they are quantum mechanical or not.) There are two forces for two isolated hydrogen atoms corresponding to the Coulombic force of attraction between the proton and the electron on each atom. When you bring these particles together, each proton also feels an attraction for the electron on the other atom. So we now have two more forces of attraction. BUT, we also have two new forces of repulsion; the repulsion between the two protons and the repulsion between the two electrons. We can minimize the repulsion between the two protons by keeping the nuclei as far apart as possible and we can minimize the repulsion between the two electrons by having them form a pair of opposite spins. (Please do not ask me to explain this. It is far too subtle.,) Thus, by keeping the pair of electrons between the two nuclei, the new forces of attraction become larger than the two new forces of repulsion. BUT, it is vitally important to remember that the result is a dynamic equilibrium. If the bond gets stretched too far, the energy of the system becomes unfavorable. If it compressed too much, the repulsion between the two protons makes the energy unfavorable. The net result is a system in which there is a rapid vibrational motion stretching and compressing the bond. If memory serves -- and it often does not -- the vibrational frequency for an H2 molecule is about 1 E14 times per second. This system is often represented by what is known as a Morse potential energy diagram. You can find this on the internet.,

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