What do you acquire when you add the number of protons to the number of neutrons in an atom?

When you add the number of protons to the number of neutrons in an atom, you determine the mass number. The mass number represents the total count of these two types of nucleons (particles contained in the nucleus) in an atom. This value is important because it helps to distinguish between different isotopes of an element, as isotopes differ in the number of neutrons while having the same number of protons.

The atomic mass, on the other hand, is typically a weighted average of all the isotopes of an element as they occur naturally, taking into account their relative abundances, and is measured in atomic mass units. The atomic number is simply the number of protons in the nucleus, which defines the element itself, while molar mass refers to the mass of one mole of a substance and is generally expressed in grams per mole, reflecting both the atomic masses of all the elements in a compound or an element itself in terms of moles.