Question

10. What is a rule for determining the mass?

Answer 1

By adding together the number of protons and neutrons and multiplying by 1 amu

Answer 2

Mass number is the sum of the protons and neutrons in the atomic nucleus.

The mass number (A) is the sum of the atomic number (Z), which is the number of protons, and the number of neutrons (N) in the atomic nucleus of an isotope of an element. A=Z+N