The average atomic mass of iron : 55.85 amu
<h3>Further explanation </h3>The elements in nature have several types of isotopes
Isotopes are atoms whose no-atom has the same number of protons while still having a different number of neutrons.
An atomic mass unit = amu is a r<em>elative atomic mass of 1/12 the mass of an atom of carbon-12. </em>
The 'amu' unit has now been replaced with a unit of 'u' only
Atomic mass is the average atomic mass of all its isotopes
atomic mass X = mass isotope 1 . % + mass isotope 2.% ...
The average atomic mass of iron