How many neutrons in the ""^56Fe56Fe isotope?

1 Answer
Sep 19, 2016

""^56Fe56Fe has 30 neutrons.

Explanation:

How did I know this? Well, an iron atom has 26 protons, positively charged, massive nuclear particles. The number defines ZZ, the atomic number; Z=1, HZ=1,H; Z=2, HeZ=2,He; Z=3, LiZ=3,Li;...........Z=26, FeZ=26,Fe.............

The nucleus also contains neutrons, massive, neutrally charged particles, and to a first approximation, the sum of protons and neutrons gives tha mass of the isotope. So if the question mentions iron, I know that Z=26Z=26; it is thus simple to specify the isotopic mass if the number of neutrons is given.