In the first para, is it intended to differentiate molecules from crystals and metals? Probably it is to early in the article to do that clearly. DavidGoodman 23:11, 5 November 2006 (CST)
That's something that I did not change from the original WP article (the inclusion of the word metal). I like waht you are doing and I think you should go ahead and change it to read better. Your work helps so much! I've been doing more on Medicine, because of slow and absent saves on the pilot, I've been working on a word document and will get it in sometime over the next day. I had a concussion in a car accident and so am not as speedy as I would like to be. Regards, Nancy Sculerati MD 10:27, 6 November 2006 (CST)
- Now that more editors and writers are on board, the few of us at the first won't have to cover quite so much territory--I hope. All of us wanted to get as many articles as possible started, but I don't think I will be able to finish all I've started. I thought I would be using word, but Firefox 2.0 has an excellent very fast spelling checker Hope you're better. You might want to start the article for it.:) DavidGoodman 20:54, 6 November 2006 (CST)
Taking the lead from the Biology article, "Biology is the science of life." I would like to suggest this article could be structured around the opening statement of "Chemistry is the science of material."
This follows from the Systems Theory model of the universe wherein components are linked by the flow of three (3) fundamental items:
- Energy (Physics)
- Information (Computer Science)
- Material (Chemistry)
On the map of General Systems Theory (GST), Biology is the next step in system complexity having components capable of accepting and delivering energy, information and material in a self-maintaining open system of the cell (the fundamental unit of life). The current introduction of the Chemistry article jumps directly into models of atoms and molecules on the pico- and atto-size scale. While I agree an understanding of what is happening at the "small" is necessary, these modules are only tools for plying the science of materials.
When I introduce "chemistry" to my university students by asking them to find a chemical in the room, they start hunting for a hidden beaker or test tube of colored liquid. The concept of "material" liberates them from thinking chemistry is only about the "small" and moves their concept of chemistry out of the laboratory. Your thoughts? --William Weaver 06:25, 18 December 2006 (CST)
I like that a lot. After all, it is both true (if not totally conventional) and makes the basic concepts of chemistry more accessible.Nancy Sculerati MD
The addition there of "interacting" should be considered: Chemistry is the "science of interacting material". Seems somewhat more appropriate as chemists dio not care about non-reacting agents :) Besides concurring with the definition that chemistry studies the INTERACTION between atoms and molecules it seems a very true notion. Robert Tito
"Chemistry is the science of interactions of electrons of materials." Robert Tito
That change does not make sense to anyone who doen't already understand chemistry. I put it back the other way. Nancy Sculerati MD
I disagree here, what makes chemistry differ from physics is the basic interactions of electrons of atoms/molecules or generic material. If you forget the elementary electrons the basics of chemistry is harmed and the difference between physics and chemistry becomes more vague. Mentioning electrons at the core of chemistry makes it different from physics because there generally matter interacts, not only electrons. And yes maybe knowledge of electrons makes one bias, but forgetting the fundamentals makes one ignorant about chemistry as opposed to physics. That in my opinion is a bad beginning. Robert Tito I just have learned that two beams of protons moving at high speed and interacting upon collision belongs to chemistry and not to physics Robert Tito I stress out I do disagree with some of the latest additions as they are not correct in displaying the science of chemistry and its fundings. Dr. Robert Tito
Robert, I can appreciate your concern about the differences between Chemistry and Physics. As an Analytical Chemist, with specialization in spectroscopy, I'm often confused for a Physical Chemist and I don't seek to separate the disciplines of physics and chemistry. Chemistry is built with physics as a foundation, so it is impossible and not even desirable to separate the two. In my undergraduate program, I teach courses in all three disciplines of Physics, Chemistry and Computer Science and I admit and rely on my bias for General Systems Theory. When my students think of Physics, they think of the progression of:
- displacement (delta position)
- time displacement (delta time)
- velocity = displacement/delta time
- acceleration = velocity/delta time
- mass (the concept from chemistry of material)
- momentum = mass * velocity
- Force = mass * acceleration
- Work = Force * distance (displacement if conservative force)
- delta Energy = Work
- Energy = Kinetic (motion), Potential (position in field), Potential (mechanical, springs), Potential (chemical, bonds), Electromagnetic
- Thermodynamics = Work as function of the system variables of Pressure (Force/area), Volume (displacement^3) and Temperature (kinetic energy)
This larger view of Physics, including the mathematics of differential and integral calculus, vectors, dot products and cross products does not include a discussion of electrons. I don't share your view that Physics and Chemistry only differ by the basic interactions between electrons and atoms/molecules. I would value your thoughts. =] --William Weaver 20:38, 18 December 2006 (CST)
After being introduced to both physics and chemistry, and having - even just elementary knowledge of both sciences, it is perfectly ok to let kids know the distinction between chemistry and physics isn't always clear. BUT as a starting remark about what chemistry is for first timers I opt for the didactic model of restriction: seperate both sciences and explain both as "separate science". Then when the need becomes clear - and at that stage the understanding of those you are teaching 'your' science one cannot go without the other. I do think however many organic chemist will not agree but as physical chemist I know it to be true. So pure fundamentally where chemistry is the interaction of matter due to the interactions of their electrons, physics is the interaction of matter without just these electrons. Here you created a clear separation. When the foundation is clear also conceptually it is possible to show similarities and overlaps. Even when describing thermodynamics it is getting hard not to use physics, mathematics being the aid-science for all beta-sciences or nature sciences (or what name you give them) (Being Dutch sometimes your terminology is strange. But as a lector as well as a teacher I started small and extended knowledge only after the basics were assimilated by the students. [The difference in educational systems is profound so it makes no sense to indicate levels under pregraduates, where - correct me if wrong - graduates are starting at the university and these should or can end with their masters.] I teach to all of university and pre-university the top-levels (chemistry - biochemistry and computer science).
Let me know your thoughts about this
I loved the ideas in I learned in chemistry, and I loved the labs and I would love this article to convey some of what chemistry is to a person who really does not know. Of course the article aslo has to be true to you experts, but that is not it's purpose here , is it? Not to exactly define chemistry to an expert but to acurately introduce it to a novice. Imagine a very smart person who speaks excellent English but, for what ever reason, never went to school. Never took even a high school science course. Can you use words and pictures to give them the ideas that make chemistry so exciting and important? I say it's ok to use words like atom and molecule and elements - as long as you expalin them somewhere in an early section. But to assume that the phrase "the First Law of Thermodynamics" explains anything to this person who is reading the citizendium article on Chemistry because he's always wanted to know, really, what Chemistry is, is a problem. Same story with the electrons, outside of the question of the fundamental importance of electrostatic forces in chemical bonds, and just where that comes into defining Chemistry, it's a word (electrons) that does not mean anything much to a person who does not already know what chemistry is, and so these concepts have to be explained in plain language. Can you do better? (it ain't easy - but it's worth it!) Nancy Sculerati MD
it is not if I can do better but if WE can do better. Anyone able to speak perfect english in your anology must have had education and up to a certain abstraction level, so that argument really isn't valid.
My problem with your introduction is it states physics = chemistry because both tell the story of interacting substances. Now you have created a problem because when the two sciences describe the same why create two sciences, one would suffice. Pupils in my country are not introduced to the basics of chemistry untill age 14/15 (third year secondary school) where they do have had physics and mathematics when they entered that school. Taken that into account and assuming people without any knowledge are unlikely equipped to use a computer let alone come up with the terms for either physics or chemistry it seams clear the difference between these two sciences can be put forward and laid down as being basically whether electrons are involved or not. I fail to see where the situation in your country, china russia or any other country would lead to any other opinion. Assuming uneducated people would use a computer to start browsing for rocket science knowledge basiccaly assumes they have KNOWLEDGE of that else they were incapable of looking for exactly that topic. The point here to make is what level DO we want to tell our story? Because it is a fascinating story one with many stimulating parts and details. To catch the attention of anybody would be nice but I wonder at what level any abstract science such as either physics, mathematics or chemistry can be taught other than that the readers should have a psychological ripeness to be able to think abstract. In general that is 14+, and these persons do know about electrons, atoms and protons. They might not know details but they know of their existence. Build upon what you can assume to be a basic building block and construct the house that is called science upon that. Lets build this together but let it be the true story
As another opinion, I think using a scientific definition not suitable for this general article. It is indeed hard to make exact distinctions--consider the very real distinction been Chemical physics, and Physical chemistry,which I understood as the distinction between the quantum mechanics of molecules, and the physical behavior of different substances. (but note the change of title for the journal, "Physical Chemistry Chemical Physics" and the Journal of Chemical Physics' self-definition at ) The same is true in the other direction--biochemistry, as possibly differentiated from chemical biology , which to me means the chemistry of natural compounds) Or even worse, Biophysics. As for chemistry dealing with the ehavior of electrons, cond=sider the field of nuclear chemistry.
the operational definition is what chemists, or physicists, or biochemists do, but there are quite a lot of people with joint appointments and where anyone stands seems determined by which department hired him first. The alternative is what chemistry courses typically teach, as distinct from physics courses. Warren, you may from necessity teach calculus, but that does not make calculus part of physics. In the other direction, mathematics departments have been known to consider classical mechanics as part of their subject, and that is where the Library of Congress puts it.
The concept we are getting at is of course known as the hierarchy of the sciences, which deserves an article of its own.
But we still need to write an article about chemistry. And saying "chemistry is the science of materials" ignores the distinction between it and materials science.DavidGoodman 23:29, 19 December 2006 (CST)
Chemistry is not simply the science of materials. Chemistry is the study of matter, AND of the changes matter can undergo. (I would prefer "matter" to "material" to avoid the confusion with "materials science".) As to bringing electrons into such early prominence: while they do indeed form a distinction between much of physics and much of chemistry, it is at the expense of portraying what chemistry is all about. Surely most chemistry is based on electrons, but how many times does an analytical chemist use the word "electron" in a typical day? I think you would draw more readers in if you focus on what kinds of things chemists do, rather than trying to start by defining your own unique box and working out from there.
While I've got the talk page open, what's with that bit about catalysts in the introduction? The placement implies that catalytic processes are one of two or three major areas chemistry is concerned with. And a wording note: catalysts do not drive a reaction. They facilitate a reaction by providing an easier pathway. And in photochemistry, the photon is usually consumed, so it's not acting as a catalyst. Jim Ford 9 Feb 2007
-addendum 7:02 pm est: OK, I got the signature thing down. Sorry about the newbie errors. Jim Ford 18:03, 9 February 2007 (CST)
The opening statement is used to distinguish chemistry from physics - the reason for the emphasize on reactions, reactivity and electrons always playing a role. Basic to chemistry is the involvement of electrons. As to material - that should be matter (no dark matter - and that might lead to confusion as matter is energy) hence the ambiguity. Photons are not absorbed - the energy of the pfotons however is - and as such devoured (in a somewhat plastic way). So far the emphasize on the role of electrons in reactions and reactivities is in its right place, the more detailed descriptions are better left at their appropriate places. As such the introduction was intended to make a distinction between biology (life) - physics( matter or energy) - chemistry (material; through electrons) - even though material is not the perfect term to use. In their three distinctive destriptions is an easy and simple difference introduced. Scientifically not right but didactical-educational in order. Robert Tito | Talk 16:49, 9 February 2007 (CST)
what it takes to major in chemistry, etc
since many high schoolers may look at this subpage website, it might be nice to give them suggestions on how to major in chemistry in college and the possible career options that exist with a BS, and with a PhD. Also, possible classes that many universities require for chemistry major would be nice. -Tom Kelly (Talk) 03:51, 19 December 2006 (CST)
This seems a nice addition yes. Maybe even a primary school addition would be appropriate. The first being somewhat more into the science the latter more into the phenomenology. Compare to the cooking experience and the chemistry of cooking. Using that approach might make chemistry more comprehensible and approachable for those without abstract thinking capabiliies and/or knowledge of abstract science. A problem however in the first target is the extreme detail into which research has grown into, so while remaining to present a helicopter view it needs to contain something like pinpointing inte details that might sparkle interest and curiosity. Cassiopeia 11:14, 19 December 2006 (CST)Robert Tito
The career aspects would often be covered by such an article as "Chemist" , and other aspects as "Chemical Education" DavidGoodman 23:30, 19 December 2006 (CST)
SO far all good points but how to incorporate all views and all visions, as one is regarded as shallow and the other as too scientific, either we integrate or dessegrate: science being the science, popular chit chat being the ""shallower approach"" (no pun intended) For all visions pro and contra can be mentioned, now to do what chemists major in: synthesis.
They have childrens enclycopedias... why can't we have children wikis linked for topics that could put in children's encyclopedias similar to how we have links in approved articles to draft pages. Also, if this happened, we could make a "children's wiki" search engine - giving articles appropriate to children of specified age ranges. this might be biting off more than we can chew... however, with everyone in the world editing, who knows? -Tom Kelly (Talk) 21:03, 20 December 2006 (CST)
Great to see activity here--I was afraid we'd only see articles about biology and health sciences! --Larry Sanger 21:17, 20 December 2006 (CST)
I second Larry's comment... I'm delighted by this discussion.
In order to construct an encyclopedia entry for Chemistry through the collaborative efforts of multinational experts, may I suggest we may wish to focus on a common definition of the science before we embark on detail.
I am quite taken by the first statement of the Biology article "Biology is the science of life." After that common mission statement, the rest of the article flows rather nicely. I don't know what the Chemistry mission statement should say, but I hope that it would be both simple and correct.
If I may use a parable, I compare our current discussion to my own introduction to the aviation industry. While at my first aerospace meeting attended by several hundred engineers, I received the following introduction to the industry:
- The most important concept is lift
- It's all about propulsion
- If you don't have modern avionics, you get nowhere
- Planes wouldn't last long without traffic controllers on the ground
- It all begins with the proper metal alloys
- A plane is just an engine container
- You have to know your mission before selecting the aircraft
- The secret is Computational Fluid Dynamics
- A trained pilot is the most important component
While every engineer had their own viewpoint, I was swamped by random (yet important and true) details. I finally met up with a grizzled, retired expert who stated "The aviation industry is a method of transportation." Each contribution I made to every project from then on was consistent with that foundational statement.
Can we hammer out a simple mission statement for the science of Chemistry? --William Weaver 21:59, 21 December 2006 (CST)
that shouldn't be hard because chemistry is the science of (interacting) matter
Now thats filled the details (and yes I will stipulate electrons :) ) [physics might go by the phrase: **** is the science of matter and it's interactions]
The idea of the chemistry for kids wiki is appealing - but count me out there it is not without reasons chemistry is taught in my country after student reach ±15. Teaching I can but not to primary school kids.
Yes, do explain the difference between chemistry and physics. Isn't it the case that chemistry concerns everything from atoms up to complex compounds and their interactions? Maybe I'm really just confused about the difference between Nuclear Chemistry and Nuclear Physics, not that I claim to understand much either one of them. --Larry Sanger 23:48, 21 December 2006 (CST)
- Yes, but when those complex compounds are traveling east at 55 mph from Pittsburgh, and another set of complex compounds is traveling west at 65 mph from Philadelphia and they collide and get stuck together, to explain the result of the process you need to use the tools of Physics. Physics is a science of the small and the large. I think Robert has it right in that a definition should include the context of "chemical reaction". I still stand that Chemistry is the science of stuff... stuff meaning matter, i.e., material, while Physics is the science of energy (kinetic, potential(fields, mechanical, chemical, thermal, electromagnetic)). Physics needs matter to study the interactions of energy and Chemistry needs energy to study the interactions of matter. --William Weaver 04:56, 22 December 2006 (CST)
As a matter of fact that difference might be - for beginnings - easy to explain if you use metaphors. Not common in starting a subject. If I were to put it, I would try to say it like this: chemistry describes the properties of all matter and its interaction viewed like a sticky ball: either matter sticks apart totally or it loses some part changing the properties of the original substances into new substances or matter. Physics does it the same way it also studies the properties of matter but based upon the hard ball image atoms and molecules tend to show. (Matter can bounce off other matter). Physics is trying to understand what is inside the matter, either by destructing it or fusing it with other matter to get different resulting matter. This resembles chemistry but where the basic matter in chemistry doesn't change (atoms stay the same atoms, protons, nuclei and electrons stay the same) in physics that is not necessarily the case. In physics you can see radioactive atoms decaying into different atoms with different chemical properties, where in chemical reactions atoms or molecules create different molecules, but the atoms remain the same.
No matter how true it is that E = mc2, people do not understand (in general) that it unequivocally says: matter = energy and visa versa. But in general you are correct stating physics is the science of energy where chemistry is the science of matter. Only in a later stage would I refer to Physics needs matter to study the interactions of energy and Chemistry needs energy to study the interactions of matter. else it will be confusing like heck. /*CONFUSSED????????????????????? You won't be AFTER TONIGHTS EPISODE OF SOAP
So any agreement upon the start of a definition?
- Robert, first... I LOVE the SOAP reference... hehe!
- So I guess you have said it best.... Given our model of E=mc2, Physics is the science of the Left side of that equation and Chemistry is the science of the Right side. That doesn't make for a good definition, but is that what we are talking about? --William Weaver 07:01, 22 December 2006 (CST)
Any objections against this text to describe/define chemistry opposed to (but not against) physics?: "Chemistry is the science that describes the properties of all matter and its interaction viewed like a sticky ball: either matter sticks apart totally or it loses some part changing the properties of the original substances into new substances or matter. Physics does it the same way it also studies the properties of matter but based upon the hard ball image atoms and molecules tend to show. (Matter can bounce off other matter). Physics is trying to understand what is inside the matter, either by destructing it or fusing it with other matter to get different resulting matter. This resembles chemistry but where the basic matter in chemistry doesn't change (atoms stay the same atoms, protons, nuclei and electrons stay the same) in physics that is not necessarily the case. In physics you can see radioactive atoms decaying into different atoms with different chemical properties, where in chemical reactions atoms or molecules create different molecules, but the atoms remain the same. Compare to E=mc2, where energy is under investigation of physics and the material properties are the field covered by chemistry."
For the kiddie wiki, I rest my case, anybody feel free to try that one. Other than using phenomenological descriptions seems vain there, because the science eludes abstract description. It is like looking at critical phenomena. There is no real scientific model there so a phenomenological, descriptive way is used. Is it science? Not to me but it is what we have and we will have to do with it until such knowledge is made available.
Chemistry base page
First of all, happy and healthy new year to all. The base chemistry page seems pretty much ready to start the approving stage. Any thoughts about entering it? Robert Tito
This article is really starting to get good. I know there are hyperlinks, but if there was an explanation of what an atom, molecule, ion etc. was, rather than just have these words hyperlinked, a persom might be able to follw the text and really learn what chemistry is.
According to me that was one of your negatives pointing at complexity. If I were to say that an atom is the smallest elementary particle (besides quarks and such) that have similar chemical behavior and can be catagorized according to chemical properties, it stetates what an atom is, but to completely explain the world of atoms and molecules you need a lot more (even quantum mechanics play a part there. Because of the complexity behind it I suggest to let the linked articles do the explaining. Many do have a notion about atoms and molecules as of the age 6-8, and making this part of citizendium incomprehensible by too complex a description seems not what we strive at: true correct and complete representation of chemistry. [[User: Robert Tito}Robert Tito]]
I would like to remove the following sentence: 'Chemical synthesis of materials involves using the known properties of molecules to predict the outcome of interactions between different substances in bulk.' Does it really make sense? Yes it does make sense, as you predict the outcome based upon science, please formulate another way if you want. Robert Tito | Talk 15:31, 5 February 2007 (CST)
'Chemical synthesis of materials involves using the known properties of molecules and reactivity, as well as reaction kinetics to predict and explain the outcome of interactions between different substances in bulk'. Especially newly discovered reactions were not always predicted (correctly) when performed the first time, but most of them can be explained afterwards in terms of their reaction kinetics and involved elements or molecules.'
Stefan von Berg is that somewhat more consistent then?? Robert Tito | Talk 14:15, 6 February 2007 (CST) much better! Stefan von Berg I leave it up to you to put it in its rightful place then :) Robert Tito | Talk 14:56, 6 February 2007 (CST)
I would like to change the first part of article to the following:
Chemistry is the science of materials. Chemists consider that all of the materials in the world are matter, primarily made up of atoms. The combination of at least two atoms connected by a chemical bond leads to molecules. Ions are derived from atoms or molecules by loss or gain of one or more electrons leading to charged particles. Salts are composed of cations (positively charged ions) and anions (negatively charged ions), so that the product is neutral (without net charge). Chemists use their view of matter at the atomic to molecular level to explain how different materials interact, and how they change under varying conditions. Chemists can induce practical changes of substances, and make new compounds including drugs, explosives, cosmetics and foods. Chemical synthesis of materials involves bringing together substances in bulk under conditions that they can interact to give different substances. These interactions are called chemical reactions, and always involve rearrangement of electrons around the reacting atoms of each molecule.
The formation of bonds between atoms or molecules means sharing electrons between the composite atoms, and this can transform one substance into another; such as the synthesis of water (H2O) from two gases: hydrogen (H2) and oxygen (O2). Some chemical interactions require energy: the substances must be mixed and heated for a chemical reaction to occur. These energy requiring reactions are called endothermic reactions. Whereas other chemical reactions release heat, and those energy releasing reactions are called exothermic reactions. On a molecular level, reactions can also be initiated by the addition or removal of electrons using electromagnetic radiation (light). Stefan von Berg
lab pipets picture
A pipette is a pipette, be it an eppendorf of 1 µl or 1 ml to a glas pipette of 100 ml, or a burette of 150 ml. As example you will see eppendorf pipettes in nearly any lab. They are called eppendorf and no longer pipette. Robert Tito | Talk 01:16, 18 February 2007 (CST)
APPROVED Version 1
Cleaned up subdiscipline sections
I have expanded and reformatted the subdisciplines section, giving increased attention to organic chemistry and polymer chemistry (the two largest subdisciplines in terms of active researchers). I have also separated non-chemistry disciplines like materials science (engineering) from the list of sub-disciplines and created a list of "closely related fields".
I have also revised some factual errors, especially the definition of organic compounds given (incorrectly) as follows:
An organic compound is formally defined as any compound bearing one or more covalent bonds between two or more carbon atoms.
This definition excludes dozens of single-carbon organic compounds (methane, chloroform, methanol etc.) and doesn't jive with any textbook definition I can find. The truth of the matter is that organic compounds are described the same way that the U.S. Supreme Court describes pornography: you know it when you see it. The definition of an organic compound is arbitrary and complicated and I don't think that a discussion about carbonates, cyanides, and inorganic carbides really fits the scope of the article. I have corrected this to simply read "organic chemistry is the study of organic carbon compounds" - although "organic carbon compound" is internally redundant, it communicates the scope of organic chemistry without burdening the reader with o-chem's dirty laundry.
Jacob Jensen 12:54, 4 April 2007 (CDT)
- I agree that the definition An organic compound is formally defined as any compound bearing one or more covalent bonds between two or more carbon atoms. presently in the article is unsatisfactory. If I were an editor reviewing this article, I would not have let it pass through. The "... study of organic carbon compounds" is much better, although I would have said more simply "... study of carbon compounds" or "... study of compounds containing carbon" or similar language. The few exceptions here are not that important to list in this broad article. An article more specifically on Organic compound might be the place to mention the "inorganic" exceptions. Henry A. Padleckas 07:54, 22 February 2011 (UTC)
I removed two "see also" topics without much use: unsolved problems, no need to put that in an encyclopedian article about chemistry, and perfection - as it remains unclear what is meant, perfection of what? Robert Tito | Talk 17:49, 23 April 2007 (CDT)
Vote 'Chemistry' for Article of the Week, 1st November anniversary!
Orbital picture incorrect?
Shouldn't the "d" orbitals have four lobes shaped like a wide X? Let's double check these before making it an article of the week. By David E. Volk? Added by Paul Wormer
- Shown is a orbital. David has in mind the orbital. Respective mathematical expressions:
- See spherical harmonics for my version of the orbital pictures. --Paul Wormer 10:11, 27 October 2007 (CDT)
Please explain draft principle
I see some things that must be changed (e.g., a wikilink to water). But the edit button is gone. I have the same problem with Van der Waals equation. If I change something in the draft, who is going to take care of this resulting into a change of the definite article? A robot?--Paul Wormer 10:19, 27 October 2007 (CDT)
- Here's how that works, Paul. Each approved article is assigned a version number, just like software. The approved version of this article is Version 1.0. It will stay static until there is a "new release", Version 1.1, and so forth. See Talk:Biology/Draft for an example of numerous approved versions, minor and more substantive. The take-home message here is that the changes made to a draft get rolled in on the next approved version of this article. I've not looked at your changes or the extent of them, or even whether you've made any, but at any point you feel the draft article is ready to become Approved Version 1.1, just say so and I will assist you with the steps. They're easy, but there is a small learning curve the first time through. Stephen Ewen 03:27, 29 October 2007 (CDT)
Changes I made on 15:24, 27 October 2010 and 15:24, 27 October 2010 removed the links to the Atoms and molecules article which was deleted because it was deemed unnecessary.
The links were found in the "Atoms" and "Molecules" subsections. I've placed links to the proper Atom and Molecule articles, in the respective subsections, instead. Matt Arenas Mercado 15:34, 27 October 2010 (UTC)