Question

it's an opportunity for gaining many points by answering easy questions
so, my question is what is defination of atomic mass ?

Answer 1

Answer:

The atomic mass of an atom is an empirically measured property, which is equivalent to the sum mass of protons, neutrons, and electrons that make up the atom (with a small adjustment for nuclear binding energy).

Answer 2

Answer:

Together, the number of protons and the number of neutrons determine an element's mass number: mass number = protons + neutrons. If you want to calculate how many neutrons an atom has, you can simply subtract the number of protons, or atomic number, from the mass number.