smaerd
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Identifying Polyatomic Ion Charges?
So I am in school right now, and I have to learn a big big list of polyatomic ions and what charges they have(Cations or Anions and to what degree).
I'm sure most of you have had to do this as well.
I personally am terrible at memorization without application. However I learn a lot from knowing functions/algorithms of things.
Is it possible to calculate the charge a simple compound has? Bare with me please as I am surely a chemistry noob!
For example: CO3(Carbonate) has a charge of - 2 e.
Carbon - Protons: 6 | Electrons: 6 | Nuetrons: 6
Oxygen - Protons: 8 | Electrons: 8 | Nuetrons: 8
?
I can see there is a difference of 2 protons, electrons, and nuetrons between both elements, but I still couldn't say if that's a valid way to
calculate the ionic charge of a simple molecule.
Or am I just going to have to memorize these things and hope they stick with me for the rest of my life?
[Edited on 4-2-2010 by smaerd]
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watson.fawkes
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Quote: Originally posted by smaerd  | | I personally am terrible at memorization without application. However I learn a lot from knowing functions/algorithms of things.
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Learn the periodic table. The patterns you're looking for are there.
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smaerd
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Thanks for the response. I didn't think to look at it like that  .
Okay so I just noticed for this example, Carbonate(CO3).
Oxygen is in group 16 while Carbon is in group 14, thus 14 - 16 = -2(e).
So it has to do with the electron differences / Atomic Number between elements in the compound?
But how does one choose which element to subtract from?
Is it whatever is listed first in the molecular structure?
[Edited on 4-2-2010 by smaerd]
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watson.fawkes
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No. At this
point, go read about the periodic table and where it comes from.
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woelen
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The periodic table indeed explains many patterns, but unfortunately you still have to memorize quite a few things:
Some examples:
- carbonate, CO3(2-) and oxalate, C2O4(2-) both are common oxoanions of carbon, in carbonate the oxidation state of carbon is +4, in oxalate, the
oxidation state of carbon is +3.
- sulfate, SO4(2-) and sulfite, SO3(2-) have sulphur in oxidation states +6 and +4.
- A common anion like thiosulfate, S2O3(2-) has one sulphur in oxidation state +6 and the other in oxidation state -2.
You see, there certainly is some pattern, but it is not completely evident by just looking at the periodic table of elements. So, you indeed best try
to memorize the most common ions.
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smaerd
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Okie dokie thanks Woelen. A memorizing I will go!
Thanks again Watson. I didn't mean to test your patience, I'm here to learn. Don't plan on leaving any time soon either Chemistry is my major and it's
something I adore, even though I know very little about it  .
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