Atoms of the same element can have different numbers of neutrons; the different possible versions of each element are called isotopes.

 

68,5 (13) + 12,8 (15) / 100   = The isotope is 1082.5

 

Atomic number is the number of protons, and therefore also the total positive charge, in the atomic nucleus. It is represented by (Z)

 

The Atomic Mass is the mass of an atomicparticle, sub-atomic particle, or molecule. It has representation of (A)