I'll go over the basics with you. Tell me anything you don't understand. (I'm not going into great depth right away, ask questions)
Everything we know is made up of molecules. What a molecule is determines its properties and how it reacts to other molecules. Say, a sugar,
Glucose looks like this: library.thinkquest.org...
You notice it's made up of letters connected by lines.
These letters represent atoms. C represents an atom of carbon. O represents an atom of oxygen. H represents an atom of hydrogen.
You'll see an "OH" there. That's just a way of writing an O connected to an H more easily. In other words, it's just an oxygen and a hydrogen
connected but they didn't feel like drawing a line between them.
The lines represent bonds. The reason a molecule doesn't fall apart is because of chemical bonds. There are different kinds, but they all serve the
same purpose: to hold an atom and another atom together.
A simpler diagram is one of water, or H2
Note how the two hydrogen atoms (H) are bonded to the oxygen atom (O).
We'll use the H2
O to explain atoms. But first, I'll explain the basic subatomic particles.
There are two basic properties you need to understand to comprehend subatomic particles. Those are mass and charge.
Mass is basically how much matter there is. The easiest way to understand it is weight, though weight is actually what you get when gravity acts on
mass. For now, though, you can think of something with more mass as "heavier" and something with less mass as "lighter."
Charge is a property that is less obvious than mass. When thinking of charge, think of magnets (and try not to think about electricity, that's a
different thing entirely). There are positive charges and negative charges. Opposite charges (like a -1 and a 1) are attracted to eachother, like
the north and south pole of a magnet. If something has a charge of 0, it is neutral, meaning no charge, and no electromagnetic effect on a charged
For this, use this diagram as an aid while I explain: www.sciencebuddies.org...
There are two basic parts of the atom: the nucleus, and the electrons that orbit the nucleus (sort of like the Earth orbits the sun, in a way).
The nucleus is made up of protons (green in the diagram, with the + in the middle of them) and neutrons (red in the diagram).
The proton has a mass of 1 (1 atomic unit, don't worry about how this translates to something you use, like pounds or grams). It has a charge of
positive 1 (+1)
The neutron has a mass of 1 as well, but a neutral charge of 0. That means it is as heavy as the proton, but without the charge.
Now the electrons orbiting it have almost no measurable mass. For all practical purposes, we can say they have a mass of roughly 0 (it isn't exactly
0, but when learning basic physics this negligible mass isn't important). However, it has a charge of negative (-1), which is exactly opposite to
the charge of the proton. This is why the electron is such a strange particle to physicists: it has such a strong charge, just as strong as the
proton (though negative, while the proton is positive), but it only has a tiny fraction of the proton's mass.
So now go back to the diagram. You see the electrons orbiting the protons and neutrons. The electrons don't fly away because they're attracted to
the protons (why they don't crash into the proton is another thing, that's for later).
You should (or maybe not, I have no clue) be wondering: what makes a helium atom (He) a helium atom, a hydrogen atom (H) a hydrogen atom, and an
oxygen atom (O) an oxygen atom?
The answer is the number of protons. An atom with one proton is hydrogen, two protons is helium, and so on. Oxygen has 8 protons.
Okay, that's it for now. This is a lot at once, so ask questions about everything you don't understand. Even ask them if you do, since I need to
know where else to go.
[edit on 24-12-2006 by Johnmike]