Chemical Nomenclature - not on MCAT?

[Twitch]

Hi All,

I'm taking CHEM I and we went through a cycle of naming chemicals. I scanned the topics.pdf on AAMC that lists all the topics tested and was just curious if anyone noticed the need to know Chemical Nomenclature for what we're doing. I imagine it's really useful for chemists and all but for what we're doing - MCAT/med school?

BTW, I'm referring to inorganic chemicals here and the science behind naming them.

As far as I can tell we're not going to be tested. I have a basic idea on naming them but there are some complicated ones that requires some thought. I'm thinking our energy is better spent else where than mastering naming?

Any thoughts?

Thanks,
-Y_Marker

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[Pontifex Maximus]

It will be on there, but certainly not extensively.

 

[UCLAstudent]

I agree with Cozmosis.

 

[Twitch]

I suspected so. Thanks for clarifying guys.

BTW, y'all recommend any good web sites for inorganic nomenclature. My text sorta sux.

 

[liverotcod]

I can't imagine that you would need to know more than the names, structures and charges of common ions and ionic compounds: ferric sulfate, i.e.

 

[UCLAstudent]

I can't imagine that you would need to know more than the names, structures and charges of common ions and ionic compounds: ferric sulfate, i.e.

Right. But know how to name organic compounds (IUPAC).

 

[stoleyerscrubz]

Also know how to do the E-Z nomenclature. very simple.

Right. But know how to name organic compounds (IUPAC).

 

[Twitch]

I can't imagine that you would need to know more than the names, structures and charges of common ions and ionic compounds: ferric sulfate, i.e.

What text/sites would you recommend? I'm waiting on the 10th edition of Chemistry - The Central Science by Brown, LeMay, et al. to come in the mail next week.

Also I'm not taking Orgo yet, just CHEM I (inorganic) but thx for the advice on EZ.

 

[liverotcod]

http://dbhs.wvusd.k12.ca.us/webdocs/Nomenclature/Nomenclature.html

 

[Twitch]

http://dbhs.wvusd.k12.ca.us/webdocs/Nomenclature/Nomenclature.html

I had just found that same site through google. Man this site just lays it out. In the last 5 mins I got binary naming for both fixed and variable charged ions.

The wife has dozed off on the couch, man I feel bad, considering it's valentines weekend and all.

Thx for the link liverotcod!

 

[Twitch]

How come nitrate is
NO3¯

So Nitrogen needs 3 to fill it's valence shell, O needs 2.
How do you get 3 oxygen with 1 nitrogen and a negative charge? I don't want to just memorize it. There's got to be some reason.

It's past midnight, maybe I need to It'll come to me tomorrow morning.

 

[UCLAstudent]

The N can only hold five bonds, so that means that two of the oxygens will be attached by double bonds, and one by a single bond. Oxygen likes to have 6 electrons. With a double bond, oxygen gets one electron from each bond, plus 2 lone pairs (total of 6). With the single bond, oxygen gets one electron from the bond, plus 3 lone pairs (total of 7 electrons). This is one too many electrons for oxygen to be "happy" and thus it is negatively charged.

 

[tank you]

in the EK chem book, it has a list of ions u need to memorize.
its not that many, just stuff like carbonate/bicarbonate, nitrate/nitrite, phosphate, chlorate/chlorite/perchlorate/hypochlorite.

 

[stoleyerscrubz]

Nitrogen is trivalent but can take on 4 bonds by assuming a positive charge. The nitrogen is attached to all 3 oxygens forming a planar molecule like a carbonyl carbon. The Nitrate ion will have the Nitrogen double bonded to one oxygen atom and have seperate single bonds to the 2 remaining oxygens atoms(each having negative charge). The total charge on the nitrate molecule is -1 (+1+0-1-1)

The N can only hold five bonds, so that means that two of the oxygens will be attached by double bonds, and one by a single bond. Oxygen likes to have 6 electrons. With a double bond, oxygen gets one electron from each bond, plus 2 lone pairs (total of 6). With the single bond, oxygen gets one electron from the bond, plus 3 lone pairs (total of 7 electrons). This is one too many electrons for oxygen to be "happy" and thus it is negatively charged.

 

[UCLAstudent]

Nitrogen is trivalent but can take on 4 bonds by assuming a positive charge. The nitrogen is attached to all 3 oxygens forming a planar molecule like a carbonyl carbon. The Nitrate ion will have the Nitrogen double bonded to one oxygen atom and have seperate single bonds to the 2 remaining oxygens atoms(each having negative charge). The total charge on the nitrate molecule is -1 (+1+0-1-1)

Haha, oops, my bad. Thanks for clearing that up.

 

[liverotcod]

Nitrogen is trivalent but can take on 4 bonds by assuming a positive charge. The nitrogen is attached to all 3 oxygens forming a planar molecule like a carbonyl carbon. The Nitrate ion will have the Nitrogen double bonded to one oxygen atom and have seperate single bonds to the 2 remaining oxygens atoms(each having negative charge). The total charge on the nitrate molecule is -1 (+1+0-1-1)

Plus, it's stabilized by resonance, meaning that all of N-O bonds have approximately 4/3 bond order.

 

[Twitch]

Nitrogen is trivalent but can take on 4 bonds by assuming a positive charge. The nitrogen is attached to all 3 oxygens forming a planar molecule like a carbonyl carbon. The Nitrate ion will have the Nitrogen double bonded to one oxygen atom and have seperate single bonds to the 2 remaining oxygens atoms(each having negative charge). The total charge on the nitrate molecule is -1 (+1+0-1-1)

Thanks stoleyerscrubz! I think it boils down to this - with just the periodic table at your disposal it's not clear how the bonds would form between those two elements. There are several ways. The way you mention is how I've seen it documented after some googling.

The bottom line, it seems is that you still you have memorize the fact that NO3- is nitrate. Atleast now I know how it (the bonds) happens. I suppose there is a core set of polyatomic ions one would need to memorize - the common ones as someone else mentioned they found in EK (and other guides, I'd imagine).

 

[liverotcod]

I suppose there is a core set of polyatomic ions one would need to memorize - the common ones as someone else mentioned they found in EK (and other guides, I'd imagine).

Yes, exactly. I think that you should also know the naming conventions for metallic ions (ferric vs. ferrous, e.g.). It may not be on the MCAT, but it comes up often enough later on in chemistry and biochem that you don't want to be scrambling to look up if "ferric" is Iron(II) or Iron(III) when the time comes.

 

[Twitch]

well, as it turns out there is a method to this madness. There is a pattern in the periodic table. see if you can figure it out. Hint: the oxyanions that contain the maximum number of oxygen is the location in the periodic table denoted by the period. This number decreases as you traverse left to right. For instance, first non metal (Carbon) in period two combined with oxygen will have 2-. The next one, nitrite will here 1-. It works the same way with period 3.

Deductive reasoning 1, Memorization 0.

 

[Firkin]

I came across this old thread during a Google search, and it seemed that lot of people had liked the link previously provided about nomenclature, but it no longer works: http://dbhs.wvusd.k12.ca.us/webdocs/Nomenclature/Nomenclature.html

I found an old version of the site on the Wayback Machine, and found a working version. Posting it here in case it helps someone else in the future. Some of the links such as the link to download a pdf no longer work, but it seems that most of the others still do: https://web.archive.org/web/2008070....ca.us/webdocs/Nomenclature/Nomenclature.html