# What are the numbers of the subatomic particles in iron?

The ""^56Fe isotope has over 90% abundance.
For iron, $Z = 26$ by definition; that is there are 26 protons, massive, positively charged particles, in the iron nucleus. Given the mass of the isotope, there must be 30 neutrons, massive, neutrally charged particles, in the iron nucleus (why must there be 30 neutrons?). And of course the neutral atom has 26 electrons.