[nickto21]

Hello All,
My math professor told the class that we've never actually seen inside of an atom, only the surface of an atom. My question is:
How do we know that there are electrons spinning in specific multiple orbits, around a nucleus, containing protons and neutrons?

I know that the things that I learn in chemistry class must be true. We use our knowledge of atomic particles everyday in industry,etc. And the results are always the same, based on the periodic table,etc.
It just seems very weird to me that we know things without ever having seen them.

Also, I'm only in Chem 101, so if there is a very complicated answer, I'm not going to get it, so please keep that in mind.

Steve

[enahs]

Also, I'm only in Chem 101, so if there is a very complicated answer, I'm not going to get it, so please keep that in mind.
 

It is probably the most complicated question you can ask!

However.

You can not "see" gravity, but you can see it's effects.
You can not "see" a magnetic field, only the effects it has on other objects.

You can not see your annoying neighbor playing really loud music when you are trying to study and get to sleep early before a big test the next day, but you can feel the effects of it!


That is probably the simplest answer/explanation I can give. It is very complicated, and I for one could not answer it fully. Though I could write you a few pages with some really big words and lots of math that sounds impressive, and you probably would not get as much as the gravity/magnetic field comparison.

Much of science is like that, you can not measure/study something directly, but you can study it indirectly, and through logic, theory and reasoning you gain insight and knowledge to what you where trying to study.

[Yggdrasil]

One classic experiment which was critical to our current understanding of the structure of atoms was Rutherford's gold foil experiment.  In this experiment, Rutherford and his students shot alpha particles through a very thin gold foil.  To their surprise, most of the alpha particles passed right through the gold foil and only a few were scattered.  The conclusion of this experiment was that most of the atom was empty space, with most of the mass of the atom concentrated in a small region of space.  This description serves as the basis of our modern model of the atom (most of the mass concentrated in the nucleus, surrounded by a sparse electron cloud).

For more information see http://en.wikipedia.org/wiki/Geiger-Marsden_experiment

[resonance]

Electrons are not just a negative charge they are also a negative charge in motion. That charge in motion will give off a magentic field.  Magnetic fields can attract or repel depending on their field direction. Within an atom, all the negative charges are on the surface, so they charge repel each other, even though they are all attracted to the nucleus. This is where magnetism comes in. The electrons will move and spin in such a way that they are all magnetically attracted to each other, so they can all overcome some of their charge repulsion. Orbitals are the best shapes for the magnetic addiition and can be simulated with mathematics.

[lemonoman]

And there is STRONG evidence for what atoms are made out of.  Our current theory of protons, neutrons and electrons explains 99.999999% of the science out there.

But we don't know for certain that's how it is.

And there are particle physicists who are trying to find out.  But all that can be done is more tests, to make sure the current theory holds.

That's how all the other models of the atom got questioned and replaced...

[Ψ×Ψ]

As for electrons and orbitals, we DO have spectroscopy.

[english]

I know that the things that I learn in chemistry class must be true.

Haha yeah.  But remember all of those things we once thought were true and then they were proven wrong by later chemists.  Can't always trust the books.