Chemistry - naming chemical ions and formulas

In My Humble Opinion
1

Does anyone have any tricks for remembering the names of chemical ions and formulas? I am really struggling with this. I get my - ides, -ites, and -ates mixed up.

I can pretty much figure out cations and anions, tell if a formula is ionic or molecular, monatomic or polyatomic (shaky on that), and I know the prefixes (mono, di, tri, tetra, penta…etc) for binary compunds.

I have very little to no background in chemistry and this stuff is really baffling me.

2

Well, that’s the trick with nomenclature. It’s not always consistent. While Chlorate has 3 oxygens and a charge of 1-, Sulfate has 4 oxygens and a charge of 3-. So trying to remember what is what by name is somewhat limited.

• an ite has one fewer Oxygens than an ate (but the charges might be the same, or different)
• a prefix of per stands for “hyper” and means yet one more Oxygen (i.e. Perchlorate)
• a prefix of hypo means one less Oxygen (i.e. Hypochlorite)
• you just have to bite the bullet and memorize them

What I did was take every polyatomic ion, break it down in to its various parts, and use those parts to (poorly) draw a picture or cartoon that would serve as a memory aid.

For example: Oxalate (C2O4 2-)

First I think of a picture to associate with the word Oxalate. So to me, I read the word Oxalate and I think of an Ox. Next I take the formula (C2O4 2-) and break it down into it’s parts: two C’s, four O’s, two minuses. Now I make a drawing of the associated word (an Ox), but I use the components of the ion to do so. So for the Ox, the C’s became the horns, the minuses became the Ox’s two closed eyes, and the O’s became a word ballon of the Ox saying <m-O-O-O-O!).

Apologies in advance if the following ascii doesn’t work:



     (_____)      __________
      –  –       /m-O-O-O-O | 
       oo       <___________/
       =

If you are super organized, use flash cards. I would try memorizing a few at a time, and then go do something else for a while. Maybe start with the easy ones like Hydroxide, Cyanide, Peroxide, Ammonium, etc. Then work your way through the various families (Chlor, Phosph, Carb…). If you use the cartoon method, your goal should be to perfectly picture the drawing in your mind whenever you hear the word.

You might also try this java flashcard site.

3 


     (_____)      __________
      –  –       /m-O-O-O-O | 
       oo       <___________/
       =

:eek:

I don’t think I’ll forget oxalate now. Seriously, that is really cute.

Thanks for the site link, I’ll try that.

4

Just remember to spell mOOOO with 4 O’s.

Or spell moo with two, and count the nostrils as the other two.

If I find my cartoon drawings around, maybe I will post a link to them or something.

5

A trick I used was that -ate has an a in it and -ite has an i in it. Since -ate vs -ite are about the number of Oxygen atoms, I remember that an a looks more like an O than an i does, so the -ate has more O atoms in it than the -ite.

Also instead of memorizing charges you may be able to determine the charges by drawing lewis structures. You’d need to know the rules of drawing lewis structures though. Stuff like the more electronegative atoms go on the outside, you can only have 8 electrons per atom in row 2 of the periodic table but 12 or more on rows 3-7 of the periodic table, charge is determined by group, sigma bonds and pi bonds count as 1 e- but lone pairs count as 2 e-, the more electronegative atoms prefer lone pairs, how to assign charges to individual atoms, etc.

6

While helping teach a chem class, it hit me that hypo means “under”, as in “hypodermic” - “underskin”.

I don’t forget hypo any more.