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Re: Random Chemistry
Posted By: [Spacebar], on host 142.59.135.51
Date: Saturday, November 25, 2000, at 12:02:18
In Reply To: Random Thoughts--Brought to You by The Cheesemeister posted by Den-Kara on Friday, November 24, 2000, at 23:46:22:

> Anyway, it wasn't until about five minutes ago that I realized I have a speech on Monday and a Chemistry test on Wednesday. Since I have absolutely no idea what the difference between an ionic compoud and a ternary compoud is (or even if one exists), I'm pretty much in a rather low position.

> ~Den-"I don't care how cold it gets, I just want it to snow"Kara

The subject of ionic and ternary compounds is fairly simple. Unfortunately, it can get a lot more complicated if you study it in a lot of depth -- not that it's complicated to understand, it just has a lot of little details that you need to know. I'll answer your question about ionic and ternary compounds at an intermediate level. Depending on how much detail your chemistry course goes into, this may not be sufficient; on the other hand, it may contain way more information than you need to know. If you have any other chemistry questions, feel free to ask -- I'll see whether or not I know the answer!

In the first place, asking about the difference between ionic and ternary compounds is like asking the difference between automobiles and trucks (for lack of a better metaphor). A ternary compound is a special /type/ of ionic compound, just as a truck is a special type of automobile. Another way of saying this might be that all ternary compounds are ionic compounds, but not all ionic compounds are ternary compounds (that is, all trucks are automobiles, but not all automobiles are trucks). I hope that makes sense.

I'll take ionic compounds first. In brief, atoms on the far right hand side of a periodic table -- the "noble gases" -- exist in a special state. They have all of their "electron shells" completely filled. Without going into great detail, I'll just say that this is a particularily desirable state for atoms; in other words, atoms "like" to have the same number of electrons as noble gases have.

Now, let's look at an atom like sodium. Sodium has one /more/ electron than the nearest noble gas, neon. (Neon has 10 electrons; sodium has 11). So, sodium would like to lose one electron in order to attain a state with all of its electron shells completely filled. What this translates into on the atomic level is that it takes very little energy to dislodge one electron from the sodium atom. Random fluctuations of energy on the atomic level -- bumping into other atoms, for example -- are sufficient to provide that energy and "kick off" the extraneous electron. (In fact, sodium is so likely to lose this extra electron that a sodium atom all by itself is often called a "free radical" in light of its instability.) This creates a sodium atom with one less electron (or one greater charge, since electrons have negative charge), called a "Sodium ion", Na^+1. As can be imagined, these "ions" are important in the formation of "ionic compounds".

So then, what happens to this "extra" electron that got kicked off? Well, let's say, hypothetically, that it happens to be kicked off in the general direction of a chlorine atom. Chlorine has one /less/ electron than the nearest noble gas (Argon) and so would like to gain an electron. The free electron that was kicked off of the sodium atom would be attracted towards the chlorine atom, and would join it, creating a chlorine ion with one fewer electron, Cl^-1.

So in this mixture, therefore, we have a chlorine ion with a charge of negative one, and a sodium ion with a charge of positive one. Well, opposites attract, so the sodium ion will be attracted to the chlorine ion and form an "ionic bond". The result is sodium chloride, NaCl. This stuff, of course, is fairly common; it's also called "table salt"!

If you mix lots of sodium and lots of chlorine together, then nearly all of the sodium will turn into Na^+1 ions, and nearly all of the chlorine will turn into Na^-1 ions. So they'll /all/ be attracted to each other. Every positive sodium ion will want to surround itself with lots of negative chlorine ions; every negative chlorine ion will want to surround itself with lots of positive sodium ions. The result will be that they'll all stick together in a "lattice structure" -- basically, chlorines surrounded by sodiums surrounded by chlorines and so on. On the macroscopic scale, this translates into crystals of these organized lattices -- that's why salt is a crystalline solid.

When you get a compound like this -- positive ions joining with negative ions in order to form lattice compounds -- it's called an "ionic compound".

Incidentally, this is a basic difference between metals and nonmetals -- metals form positive ions, while nonmetals form negative ions. So most ionic compounds are made up of metal ions attached to nonmetal ions. (Of course, any metal or nonmetal will do; metals like magnesium, for example, will form 2+ ions since they are two away from the nearest noble gas; "transitional" metals like copper will form several types of "wierd" ions in order to be /more/ like (but not exactly like) noble gases -- copper can form 1+ OR 2+ ions.)

But it's not always just one metal and one nonmetal. Sometimes, two nonmetal ions can join together to form a charged, covalent compound (or molecular compound, if you prefer). For example, a chlorine atom can bond with four oxygen atoms to form the perchlorate ion, ClO4^-1. It's still an ion, though, because it has a negative charge -- somewhere in there, the chlorines or the oxygens must have gained one electron. However, this perchlorate ion will bond with a sodium ion (or any other metal ion) just as the chlorine atom will. In this case, we'd get the compound sodium perchlorate, NaCl04. This is an ionic compound, just as NaCl is, but it has three atoms (sodium, chlorine, and oxygen) instead of just two. When you get that sort of situation where there's three oxygens, it's called a "ternary compound".

Of course, we're not limited to three atoms either. The acetate ion has the structure CH3COO-, but it has a 1- charge just like chlorine or perchlorate and can form ionic compounds just the same way. NaCH3COO is sodium acetate, and CH3COOH is acetic acid (yes, the kind you get in orange juice). The point is, this compound has four types of atom (sodium, carbon, hydrogen, oxygen) instead of just two or three.

Naming these ionic compounds is also pretty simple. With simple atomic compounds, it's [name of metal] + [name of nonmetal except for the last syllable] + "ide" ending -- "sodium chloride", for example. It doesn't matter how /many/ metals or nonmetals you have -- MgCl2 is just magnesium chloride, even though there's two chlorine atoms.

With polyatomic ions, like ClO4^-1, it's even easier. It's [name of metal] + [name of polyatomic ion] -- sodium perchlorate, for example. (If your chemistry class works like mine, they'll give you a "data sheet" to inform you that, for example, ClO4^-1 is called "perchlorate" and CH3COO^-1 is called "acetate").

If you don't get a data sheet, some information about naming these compounds can be found at http://www.compusmart.ab.ca/plambeck/che/p101/p01029.htm.

Good luck on Wednesday!

> P.S.
> Question here...If you tell someone they hurt your feelings and they simply smile at you rather than replying, does it mean they didn't believe you were serious? Or does it just mean they don't know how to respond to your feelings being hurt?

Unfortunately, the correct answer to this question is useless: "It depends."

-SB

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