Subatomic Particles are particles which are smaller than atoms, such as protons, electrons, nucleus, orbitals, and neutrons.
Protons have a positive charge and a mass. The number of protons determine what the atom's identity. Protons also determine the amount of electrons in an element because the number of protons should be the same as the electrons.
Electrons are the negatively charged particles of atom and does not have a mass. The amount of electrons determines the atom's reactivity to others. The electrons of an atom create a negative charge that balances the positive charge of the protons in the atomic nucleus