The term "mass number" is correct and usable in written English.
It is a technical term used in chemistry and physics to refer to the sum of the number of protons and neutrons in an atom. For example, the mass number of hydrogen is 1, because it has one proton and no neutrons.
For nuclei of even mass number, the multiple is an integer; for those of odd mass number, the multiple is a half-integer.
The successive beta decays constitute an isobaric, fission-product decay chain for each mass number.
The total yield for the entire chain is called the cumulative yield for that mass number.
A nuclide is thus characterized by the mass number (A) and the atomic number (Z).
It has been determined experimentally that the binding energy per nucleon is a maximum of about 1.4 10−12 joule at an atomic mass number of approximately 60 that is, approximately the atomic mass number of iron.
Division of the binding energy EB by A, the mass number, yields the binding energy per nucleon.
Spontaneous fission, discovered (1941) by the Russian physicists G.N. Flerov and K.A. Petrzhak in uranium-238, is observable in many nuclear species of mass number 230 or more.
It is usual to characterize different isotopes by giving the sum of the number of protons and neutrons in the nucleus a quantity called the atomic mass number.
The mass number of the nucleus remains the same, but the nuclear charge (atomic number) increases by one, and a new element is formed for each such conversion.
The resultant collisions were reported to have produced an isotope of the element with a mass number of 261 and a half-life of 1 2 milliseconds.
The term nuclide is not synonymous with isotope, which is any member of a set of nuclides having the same atomic number but differing mass number.
