What are the fundamental principles that are found throughout chemistry? [closed]








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In the same way that biology has the fundamental idea that all organisms want to reproduce and pass on their genetic information, and that evolution accounts for the diversity of life, what are some of the ideas that tie chemistry together? Apart from all the specifics, what is chemistry really about at its heart?


Apologies if this sounds like a really strange question.




This is an inherently subjective question. It's very difficult to come up with an answer that isn't just a fundamental principle of physics. My personal opinion is the following:



> 
> Chemistry is the study of interacting electrons.
> 
> 
> 


Now, obviously the electrons are only near enough to interact because the positive charges of nuclei don't let the electrons fly away. Fundamentally, however, all of chemistry can be described in terms of electron densities, which is the basis of density functional theory.


This is not just a theoretical construct either. In every field, people are talking about different types of bonds and different electronegativities. If you think about organic chemistry, reaction mechanisms are described in terms of electron-pushing, which is some highly abstract way of talking about the dynamics one might find if you could solve the time-dependent Schrodinger equation for arbitrary lengths of time.


Even things that seem to have nothing to do with electrons, such as *nuclear* magnetic resonance, are often useful because they key in information about the where electrons are localized via chemical shifts.


Also, this definition manages to distinguish chemists from physicists because very often physicists don't care about solving for the energy of something to the sixth decimal place. Whereas, as a computational chemist, I sometimes worry that I might actually need to get that electronic energy out to the ninth decimal place...


So, my opinion is that chemistry is the study of interacting electrons, and chemists care very deeply about the details of those interactions.


 7

Chemistry is different from physics in that its focus has historically been on understanding what gives rise to the variation of matter, rather than asking "what is matter", which is one of the more profound questions physics asks. By extension chemistry also concerns itself with how matter can be transformed within this manifold of possible forms. 


Chemistry is an extremely broad field that encompasses just about anything you can think of, as reflected in the great variety of subfields with hyphenated or compound names: geochemistry, astrochemistry, biochemistry, physical chemistry (not to be confused with chemical physics), nuclear chemistry, analytical chemistry, inorganic chemistry, organometallic chemistry, organic chemistry, chemical engineering, petrochemistry, agrochemistry, food chemistry, quantum chemistry, electrochemistry, among many others and including only those that include "chemistry" in their name (unlike say molecular biology, protein science, materials science and many other fields which are arguably also chemical sciences, or contain a strong chemical component). 


This is why chemists proudly state that chemistry is the central science.


For more information on the great scope of chemistry you may want to check what branches exist within a professional society such as the ACS (American Chemical Society). 


Addendum: Given the question "what are the central principles found throughout chemistry", emphasizing the role of the electrons makes sense, since describing their behavior is a key concern for understanding the structure and reactivity of compounds. But I'd say the fundamental principles are "quantum mechanics" and the "principle of charge" (the latter given as an answer elsewhere) and not restrict myself to the electron.


 3

The fundamental principle of chemistry is probably the conservation laws : energy and matter. Maybe also the universal attraction between positive and negative charges and the repulsion between similar charges. These laws have no exceptions, as far as I know.


 1

Chemistry seeks to describe, among other things, chemical changes in the world. All spontaneous changes obey a law, and that is that they increase the entropy of the universe. Hence, a fundamental principle of chemistry could arguably be:


dS > 0


 1