Question: what is the atomic mass and atomic number

title: Mass number
text: The mass number ( symbol A , from the German word Atomgewichte ( atomic weight ) , also called atomic mass number or nucleon number , is the total number of protons and neutrons ( together known as nucleons ) in an atomic nucleus . It determines the atomic mass of atoms . Because protons and neutrons both are baryons , the mass number A is identical with the baryon number B as of the nucleus as of the whole atom or ion . The mass number is different for each different isotope of a chemical element . This is not the same as the atomic number ( Z ) which denotes the number of protons in a nucleus , and thus uniquely identifies an element . Hence , the difference between the mass number and the atomic number gives the number of neutrons ( N ) in a given nucleus : N = A − Z ( \ displaystyle N = A-Z ) . 

Answer: answer: The mass number, also called atomic mass number or nucleon number, is the total number of protons and neutrons in an atomic nucleus, and it determines the atomic mass of atoms.  The atomic number denotes the number of protons in a nucleus, and thus uniquely identifies an element.