How do isotopes of an element differ?
By the number of NEUTRALLY-CHARGED nucular particles....i.e. by the number of
An atom is characterized as a particular element by the number of positively-charged, MASSIVE nuclear particles, i.e.
The nucleus can also contain neutrons, massive nuclear particles of ZERO charge. Together with protons, these particles engage in the strong nuclear force, the which, at impossibly short nuclear ranges, is STRONGER than the electrostatic force of repulsion, and binds nuclei together.
The atomic mass printed on the Periodic Table is the weighted average of the different mass numbers... Hydrogen, for which