Hadrons are made of  but they have an  electric charge.  This means that they never have a charge that is 2/3 or -1/3 or other such fraction.

They can be divided into two classes: and

 - are made of quarks.

  A proton is made of  quarks and quarks.

  Protons are  

  Neutrons are   

NOTE The only stable baryon into which other baryons will eventually decay is the .

Remember GCSE - what can a neutron decay into during the emission of Beta radiation?  A and an .  (This also produces an antineutrino.)

-  are made of a and an

One example of a meson is a pion (⁺), which is made of an quark and a anitiquark. 

The antiparticle of a meson just has its quark and antiquark switched, so an antipion   (^-) is made up from a quark and an antiquark

The kaon (K^-) meson lives much longer than most mesons, which is why it was called

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