Absolutely. An electron has a mass of 9.109 382 15.E-31 kg. That is .0000000000000000000000000000911kg. The mass of the proton is 1.672E-27 kg. The mass of the neutron is slightly larger at 1.674E-27...
electrons are part of atoms.
yes
A molucle
Salt = NaCl If you go any smaller you would need to break it apart into its two atoms: Na = Sodium and Cl = Chlorine.