A proton and neutron
In an atom.
No way?
Discovered in a cathode ray,
Were electrons.
Unlike protons,
Contain a negative charge
Though are not large.
A proton in an atom
In the top not the bottom
Is the atomic number.
With these tools you will conquer
Any test.
Taught from the best
Such as Democritus.
All the particles in the nucleus
Can be seen with microscope
To be determined an isotope?