Atomic mass is never an integer number for several reasons: The atomic mass reported on a periodic table is the weighted average of all the naturally occuring isotopes. Being an average it would be most unlikely to be a whole number. The mass of an individual atom in atomic mass units is the mass relative to carbon-12.
Answer:
This is because the atomic mass ir usually calculated as the weighted average of the masses of the different isotopes of each element taking into account the relative abundance of each of them.
Explanation:
The isotopes of an element are those in which its atomic numbers (that is, the number of protons) are equal, but the number of neutrons is different. Record that protons and neutrons are found in the nucleus of the element. The same chemical element may consist of different atoms, that is, different isotopes. Then the atomic mass of an element is the weighted average mass of its natural isotopes. Therefore, the atomic mass of an element is not an integer. The weighted average means that not all isotopes have the same percentage. In other words, the atomic masses of the chemical elements are usually calculated as the weighted average of the masses of the different isotopes of each element taking into account the relative abundance of each of them.
This produces that the atomic mass don't always be a whole number
