Question

compare and contrast ionic and covalent bonding in atoms. im in the 8th no big words

Answer 1

http://www.youtube.com/watch?v=hEFeLYWTKX0&list=PLE301768D84D6DAD1&index=4&feature=plpp_video Is a good explanation.

Answer 2

Opposite attract, eh? Boys like girls, and vice versa (once they get old enough). So we can imagine two ways in which we can build a stable arrangement of boys and girls.

(1) We could lay down a pattern, like at a dinner table with a formal dinner. Boy girl boy girl boy girl. The boys would like that -- each boy has two girls for his neighbors, and the girls would like it, for the same reason.

Let's go further and imagine that these particular boys don't much like each other, let's say because they're all rivals for the same spot on a sports team, and maybe the girls don't like each other either, for the same reason. In that case, an arrangement boy girl boy girl is going to be lots more stable than, say, having all the boys at one end and all the girls at another.

Well, this is like an ionic compound. You make it out of ions, atoms that have gained or lost some electrons, so they are either positively or negatively charged. The positive charges all repel each other, and so do the negative charges. But the positives attract the negatives, and vice versa. If you build them up in certain regular patterns, where you surround each positive with a negative, and each negative with a positive, then you can form a stable solid material. This is called an ionic compound.

(2) Here's another idea, though. What if we got two boys who both liked the same girl? You might imagine that the two boys would end up spending a lot of time together, in the same place, even if they didn't much like each other, becauset they were both chasing the same girl. Wherever she goes, they would be tagging along. But because they don't like each other much, you'd probably usually find the girl between them, and the two boys as far apart as possible.

So this is like a covalent compound. You get two (or sometimes more!) positively charged atom cores (you can think of them as positive ions if you like) who are both attracted to the same electrons. They repel each other, so they stay as far apart as they can, while also generally staying close to the electrons. The "chemical bond" between the atoms occurs because both cores are attracted to the same group of electrons. We often say the cores "share" the electrons, although you get a better sense of what's going on if you say they're both trying hard NOT to share the electrons -- but they both lack the strength to steal the electrons entirely away from the other atoms.

A few things to take away from this:

(1) The underlying forces are the same, it's the attraction of postive charged things for negative charged things, and the repulsion of positive things from each other, and the repulsion of negative things from each other. These electric forces are the root of all behaviour at the atomic and molecular level.

(2) Ionic compounds form when atoms have completely gained some extra electrons, or completely lost them. The ions can form stable compounds by forming certain patterns of ions.

(3) Covalent compounds form when atoms are fighting over the same electrons. The fight keeps them bonded to each other, and a collection of atoms bonded to each other is called a molecule.

Usually molecules are fairly small. You get a handful of atoms, maybe 10, all bonded together. But there are some very large molecules, where millions and millions of atoms are all bonded together.