As per the Dalton's Atomic theory, atoms were considered indivisible particles but later on we comes to know that atoms are made of even smaller particles know as electrons, protons and neutrons.
But now we know that even electrons, protons and neutrons are not fundamental particles.
Electrons are made up of leptons while Quarks make up protons and neutrons.
Each proton and neutron contains three quarks.
Proton - Two up quarks and one down quarks.
Neutrons - One up quark and two down quarks.
Each up quark has a charge of +2/3 while each down quark has a charge of -1/3.
Proton contain two up quarks and one down quarks this is why they a charge of +1
+2/3 + 2/3 -1/3 = +1
Neutron contains two up quarks and one down quarks this is why they have a charge of 0.
+2/3 - 1/3 - 1/3 = 0
We can say that three fundamental particles of matter should be Leptons, Quarks and Bosons.
(Complete Family)
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