I keep on getting confused between mixtures and compounds and molecules thinking that they are made by atoms forming up - I have a science test tomorrow so I want to keep it stuck in my head...
-
Atoms bond together to make molecules. That bond is like a marriage bond; They commit themselves to one another by sharing electrons. They don't fall apart later on.
Ok, so the molecules can react, and the bonds can break, but it takes a fair bit of energy to do it.
Molecules can be molecules of an element, (like oxygen; two oxygen atoms bonded together) or molecules of a compound (like water; H2O)
As for a mixture; the particels in a mixture are just hanging round near each other; they might be intimately mixed, but there's no long term bonding beteween them, so they seperate easily.
the only substances that regularly exist as atoms are the noble gases. Everything else bonds with other atoms in one way or another; to make molecules, or ion pairs, or metallic structures, or giant covalent structures. But now I'm going off and getting all complicated on you. Sorry.
Just remember that once two (or more) atoms have bonded into a molecule, they stay together until a chemical reaction re-arranges them.
Mixtures re-arrange themselves without needing a chemical reaction to do it.
Ok, so the molecules can react, and the bonds can break, but it takes a fair bit of energy to do it.
Molecules can be molecules of an element, (like oxygen; two oxygen atoms bonded together) or molecules of a compound (like water; H2O)
As for a mixture; the particels in a mixture are just hanging round near each other; they might be intimately mixed, but there's no long term bonding beteween them, so they seperate easily.
the only substances that regularly exist as atoms are the noble gases. Everything else bonds with other atoms in one way or another; to make molecules, or ion pairs, or metallic structures, or giant covalent structures. But now I'm going off and getting all complicated on you. Sorry.
Just remember that once two (or more) atoms have bonded into a molecule, they stay together until a chemical reaction re-arranges them.
Mixtures re-arrange themselves without needing a chemical reaction to do it.