How many protons and neutrons are in an atom of Fe-56?

Answer 1

Electrons do not contribute to weight of elements or if they do it is extremely negligible. They are telling you 56 for Fe and this is giving its atomic weight. The proton number which is 26 for the element Fe, or Iron is simply 26 and this tells you the number of protons, defining the element. So now if you subtract 26 from 56 you will get the number of neutrons, this is because only the protons and neutrons contribute significantly to an element's weight.

so you would have 26 protons

26 electrons

and 30 neutrons

In the elemental form (where there is no charge) the number of protons equal the number of electrons.

Answer 2

Hello,Bernice,

Iron (Fe) is element 26 on the periodic table. By definition, it has 26 protons. The total mass of Fe-56 is, yes, 56. Since the electrons are small, they are not counted as part of the atomic mass. That leaves the protons and neutrons at 1amu (atomic mass unit) each. The neutrons are the difference between the total (56) less the protons (26):

(56 - 26) = 30 neutrons

26 protons

30 neutrons

56 total amu

The periodic table shows an average amu of 55.845. That's due to the presence of additional isotopes having different numbers of neutrons. A weighted average of Fe atoms in nature leads to the 55.845 number.

Bob