When I studied physics and chemistry in school I was taught that atoms are composed of protons, nuetrons, and electrons, and that their interactions can explain chemistry and chemical interactions. Now I understand that this is either wildly oversimplified or wildly out of date. Would somebody be able to catch me up, simply, on what the smallest building blocks of out world are and how they interact to create matter?
In: Physics
The smallest building blocks are
* quarks
* leptons
* guage bosons
* their antiparticles (though some of the guage bosons are their own antiparticle)
You are already familiar with some of these.
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The quarks come in three groups, and each group has 2 quarks:
* Up and Down (the first two discovered)
* Strange and Charm (very similar to the Up and Down, but much heavier.)
* Top and Bottom (once called Truth and Beauty. Also very similar, but heavier still.)
Quarks have an electric charge, and a “color charge”
* Up, Strange and Top have charge +2/3
* Down, Charm and Bottom have charge -1/3.
* The “color charge” of a quark is not fixed.
The simplest way to think of color charge is that a quark can be red, green or blue, and quarks must form combinations with a “neutral” color:
* Eg, you can have three quarks, one of each color (red, green and blue, making a neutral “white” total color charge)
* Or, you can have a quark and an antiquark (eg, red and antired, making a neutral “black” color charge)
* Or, you can have more complicated messes: eg, four quarks and an antiquark, etc.
* There’s a [ridiculous](https://en.wikipedia.org/wiki/List_of_baryons) [zoo](https://en.wikipedia.org/wiki/List_of_mesons) of combinations, in fact, most of which are irrelevant to everyday life.
Of all the combinations of quarks, only two combos are really relevant for chemistry and everyday life:
* up+up+down: this is a proton.
* up+down+down: this is a neutron.
Any other combo will quickly decay into lighter particles.
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Leptons also come in three groups. Within each group, there are two types of leptons.
* There’s the electron, and the electron neutrino.
* There’s the muon (which is very similar to an electron, but heavier) and the muon neutrino.
* There’s the tau particle (which is also very similar to an electron, but much heavier) and the tau neutrino.
Only the electron is really relevant for chemistry:
* The muon and tau particle are not stable, and will decay quickly into lighter particles.
* The neutrinos are extremely light, and almost undetectable. They have no charge. As they travel through space, they gradually transform into one another and back again. There are literally trillions passing through us every second, with no discernible effect.
A free neutron will decay into a proton + an electron + an antineutrino, but the antineutrino flies off quickly with no discernible effect (unless you have a neutrino detector handy, but even then, it will probably just pass straight through it)
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The guage bosons are the “force carrying” particles:
* There’s the photon. That’s responsible for electromagnetic interactions, which is the main kind of interaction for everyday matter at ordinary scales.
* There are the W+, W-, and Z bosons. These are responsible for “weak interactions”, eg a neutron decaying to a proton, or s, c, t or b quarks decaying to lighter ones, or muons and taus decaying.
* There are 8 different types of “gluons”, but they’re all pretty much indistinguishable, and only operate at very short ranges (eg, within a nucleus). They’re responsible for “gluing” quarks together to form protons and neutrons, or “gluing” the nucleus together.
* There’s the Higgs boson, which is responsible for things having mass.
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It is suspected there is also a particle called a “graviton”. Just like a photon is a tiny quantised particle EM radiation, a graviton would be a tiny quantised particle of gravity waves. We haven’t been able to detect gravitons yet.
There are other particles we suspect exist, but haven’t been able to detect yet. Eg, whatever “Dark Matter” is made of.
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