Fermilab

Dear Miss Alonso,

This is a very good question, and the answer is rather complex.

The first question is "how do scientists know which atoms can give electrons to other atoms?" We know from experiments on substances and from basic scientific calculations on the structure of an atom.

If you have a sample of sodium and a sample of chlorine, you can measure how easily these substances combine. In this case, the combine very easily and release a lot of energy when they combine (this combination can actually explode violently).

In fact, all elements on the left hand side of the periodic table (lithium, sodium, potasium, etc) combine very easily with substances on the right hand side of the periodic table (florine, chlorine, bromine, etc.).

About 80 years ago, scientists accurately figured out how electrons attach themselves to atoms. From these theories, we know that lithium, sodium, potasium, etc., all have one electron that is not stuck very well to the atom. Likewise, we know that atoms like florine, chlorine, bromine, etc, have a place for one more electron to fit very snugly. So we know that sodium is really giving its electron to chlorine, in table salt.

The second question: "Can just any atom give how ever many electrons they want to another atom?" Not really. Electrons are stuck to atoms because they have a negative electrical charge and the rest of the atom (the nucleus) has a positive electrical charge. This is the same force that causes your hair to stand on ends on a dry day, or gives you a shock when you drag your feet across a carpet on a dry day.

So as you take electrons off of an atom, the remaining electrons get stuck even stronger to the (more positively charged) atom than before, so you can't just keep taking electrons off.

At places like Fermilab, we have figured out ways to take all the electrons off of an atom, leaving just the nucleus, but this it not a normal way for an atom to live!

I would be happy to continue this discussion with you via email. I'm sure that you have more questions on this complicated topic!

Elliott McCrory, PhD, Fermilab.

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