(Original post by adesola15)
A compound has more than one type of element, e.g. H20, NH3
A molecule has the same type of elements, e.g. H2, O2, N2
You're confusing the terms element and molecule here. I'll outline some of the definitions for you.
Molecules are structures formed when atoms of any element covalently bond to each other. These include beryllium chloride BeCl2, ammonia NH3 and water H2O. They also include things like H2 and O2 which contain only one element.
Here's some adorable pictures of them:
The above are water, ozone and glyphosate.
Normally molecules have a finite size, but there's also such things as macromolecules. These are a special case because the molecule can in theory be infinitely big but always has a finite size in practice. Fullerene tubes are a good example of this. Things like antibodies and enzymes are also molecules, though they're often called macromolecules due to the sheer size of them but these don't have theoretically infinite sizes. It's a bit misleading really. You can see why though when you look at this behemoth: https://www.amgenscience.com/static/...cule-image.jpg
I mean just look at this guy! This one's is human thioredoxin, another monster! http://spdbv.vital-it.ch/TheMolecula...mages/avgd.gif
If you search google images for molecules you'll get loads of these pictures, scientists make/find them and we get all like "OMG CHECK OUT THIS MOLECULE IT'S SO COOL!!!!111!!!!!" The smaller ones are just as awesome though, especially my beloved hydrogen peroxide!
One thing to watch out for is the different types of fullerenes. Some like the nanotubes and also fullerene bowls are macromolecules while others, like bucky balls aren't. You can even get fullerene tubes with bucky balls stuck to them, a structure called a 'nanobud:' http://cdn.phys.org/newman/gfx/news/...EM_cnt_c60.jpg
You can also get fullerene tubes growing inside fullerene tubes! When this occurs with bucky balls you get what's referred to as a nano-onion!
Fullerenes are awesome aren't they?
But I digress...
A compound is a structure formed when a bunch of atoms of different elements bond together. Salts and molecules with more than one element in them are examples of these. Here's some:
An element is an atom with a certain proton number. So for example, oxygen has a proton number of 8 and all atoms with 8 protons in their nucleus are oxygen atoms.
A salt is an ionic compound wherein ions are attracted to each other via the electrostatic force, which holds the compound together.
I better stop or I'll be here all night. I hope this helps!