Basic Structure & Behavior of The Atom... Oh, and hi!

[metapad]

Hiya. I've gotten behind in physics lately. Disturbingly so, in fact. I just can't stand how little I know, so I've recently undertaken the task of educating myself using Wikipedia, but it's terribly hard. I may have misinterpreted some things, and some things don't make much sense at all, so I'll be posting here every now and then.

Anyways, what I want to know, basically, is what attracts what in an atom, and what repels what. Here's what I understand so far:

Electromagnetic force dictates that protons will repel each other, electrons will repel each other, and protons & electrons will be attracted to each other. Neutrons are electrically neutral. Protons are attracted to each other because of the strong (but short ranged) nuclear force that attracts quarks within protons. While protons would normally repel each other, if they manage to get close enough to each other strong nuclear force will overcome the electromagnetic force that normally repels them and they'll be bound. I'm assuming that neutrons are also bound by strong nuclear force, and this is what creates a nucleus. Electrons are bound to atoms by electromagnetic force.

And now for some questions... Wikipedia is giving me the impression that atoms can be stuck with an extra electron. I would think this should be immediately flung out as radiation as the combined repulsion from the other electrons is stronger than the combined attraction from the protons. Is this true? Also, will an atom with a net charge of +1 transfer an electron to an atom with a net charge of -1? In what ways can neutrons affect an atom? They're electrically neutral, I would think they only add mass to the atom. And where exactly does weak nuclear force come in?

Sorry if I'm being a "help vampire," but I'm a bit confused.

[robertm]

Please Please PLEASE use Wikipedia as little as possible. It is sadly filled with errors and misconceptions. If you really care about learning physics, which I think you do, you really must get a good text book. It sounds like you are going for a University level of understanding, so I would suggest that you try and find some good used fairly recent text books and read COVER to COVER.

There is nothing wrong with using the internet as an additional source of info. but you really need to base your fundamentals on respected published works.

Here are some links for a few peer reviewed physics journals you should also look into:
http://www.iop.org/EJ/
http://www.nature.com/index.html
http://192.171.198.135/frontiers/index.asp

Good luck with your studies and hope to see you around the forums!

[vanesch]

Please Please PLEASE use Wikipedia as little as possible. It is sadly filled with errors and misconceptions.


I don't know why you say that. Most articles on basic physics are really neat. True, for things that are somewhat controversial, one has to be careful with Wiki, because anybody can change it at their will and desire, but really, if you look up things like Newton's law, ( http://en.wikipedia.org/wiki/Newton_law ) electromagnetism (http://en.wikipedia.org/wiki/Electromagnatism ), atomic structure, quantum physics etc... I find the articles in general not so bad. Of course, if something is not clear, it might also be in error, and one should check in different sources (as one should always do). And it doesn't replace more advanced textbooks. But I find the material written there for most basic things not so badly done.

[vanesch]

Electromagnetic force dictates that protons will repel each other, electrons will repel each other, and protons & electrons will be attracted to each other. Neutrons are electrically neutral. Protons are attracted to each other because of the strong (but short ranged) nuclear force that attracts quarks within protons. While protons would normally repel each other, if they manage to get close enough to each other strong nuclear force will overcome the electromagnetic force that normally repels them and they'll be bound. I'm assuming that neutrons are also bound by strong nuclear force, and this is what creates a nucleus. Electrons are bound to atoms by electromagnetic force.


That's basically correct.


And now for some questions... Wikipedia is giving me the impression that atoms can be stuck with an extra electron.


That's correct, it is called a negative ion.


I would think this should be immediately flung out as radiation as the combined repulsion from the other electrons is stronger than the combined attraction from the protons. Is this true? Also, will an atom with a net charge of +1 transfer an electron to an atom with a net charge of -1? In what ways can neutrons affect an atom? They're electrically neutral, I would think they only add mass to the atom. And where exactly does weak nuclear force come in?


In normal salt, there's a positive ion (sodium, which lost an electron) and a negative ion (chlorine, which has one too much) alternating in a crystal structure. Exactly WHY this is so, and WHY the chlorine doesn't render its extra electron to the sodium, comes about because of quantum mechanics.
On the atomic level, indeed, neutrons essentially only change the mass of atoms. However, on the level of the nucleus, they are an active player, and modify the nuclear properties strongly - but these are hidden on the chemical level (except for the mass difference).

[metapad]

Please Please PLEASE use Wikipedia as little as possible. It is sadly filled with errors and misconceptions. If you really care about learning physics, which I think you do, you really must get a good text book. It sounds like you are going for a University level of understanding, so I would suggest that you try and find some good used fairly recent text books and read COVER to COVER.

There is nothing wrong with using the internet as an additional source of info. but you really need to base your fundamentals on respected published works.

Here are some links for a few peer reviewed physics journals you should also look into:
http://www.iop.org/EJ/
http://www.nature.com/index.html
http://192.171.198.135/frontiers/index.asp

Good luck with your studies and hope to see you around the forums!

Thanks Robert. What textbooks would you recommend though? I need some books that discuss things like the structure of the atom and electromagnetism.

And thanks for answering my questions vanesch, but I still don't really understand, would a negative ion lose it's electron if it were in vacuum? If not, what keeps it in the atom?

[Integral]

The field of Physics can be seen as a structure. The foundation of this structure is the fundamentals of Mechanics and electromagnetism. To appreciate and fully understand the details of atomic and nuclear physics which comprise the upper floors of structure that is physics you must have a good understanding of the fundamentals. If you are indeed serious about learning physics start with a good calculus text and something on the order of Halliday and Resnik. When you have mastered the fundamentals then more of what you read of Atomic Physics will make sense.

It is critical that you build a solid foundation before you start with the more involved concepts of modern Physics.

[metapad]

The field of Physics can be seen as a structure. The foundation of this structure is the fundamentals of Mechanics and electromagnetism. To appreciate and fully understand the details of atomic and nuclear physics which comprise the upper floors of structure that is physics you must have a good understanding of the fundamentals. If you are indeed serious about learning physics start with a good calculus text and something on the order of Halliday and Resnik. When you have mastered the fundamentals then more of what you read of Atomic Physics will make sense.

It is critical that you build a solid foundation before you start with the more involved concepts of modern Physics.

I'm terrible with math too, unfortunately. Another one of my goals is to fix that. I'm serious enough about learning more in physics, but not for purely serious purposes. In what areas would it become vital for me to know calculus? I'm a bit reluctant to learn calculus, but if it's really important I'll have to try.

(And thanks to everyone who is taking the time to help me, I really appreciate it :) )

[G01]

In what areas would it become vital for me to know calculus? I'm a bit reluctant to learn calculus, but if it's really important I'll have to try.

If you really wish to learn physics (as opposed to learning about physics) you are going to have to learn calculus, along with other important math subjects, like linear algebra. Math is the language of physics, and, as such, it will be an integral player in any field you wish to study in depth.

[vanesch]

I'm terrible with math too, unfortunately. Another one of my goals is to fix that. I'm serious enough about learning more in physics, but not for purely serious purposes. In what areas would it become vital for me to know calculus? I'm a bit reluctant to learn calculus, but if it's really important I'll have to try.

(And thanks to everyone who is taking the time to help me, I really appreciate it :) )

You really have to learn calculus. In fact, one of the reasons why one cannot teach much very interesting physics on high-school level is that the slightest bit of serious physics needs calculus. But it really isn't that hard, you know. Find a good book on it. And then, if you want a leisurely but brilliant introduction, read the Feynman Lectures on Physics.

[metapad]

Thanks again everyone, guess I'll have to get some math books now :)

[robertm]

Mathematical Methods in the Physical Sciences by Mary Boas

I highly recommend this book. Pretty cheap too, try Amazon ect...