Answer:
The atomic number of an element is the number of protons found in the nucleus of every atom of that element. Atomic number and is used to distinguish one element from another . The number of protons define the identity of an element (i.e., an element with 6 protons is a carbon atom, no matter how many neutrons may be present).
While, Mass number (atomic mass number or nucleon number), is the total number of protons and neutrons in an atomic nucleus. It is said to be approximately equal to the atomic mass of the atom expressed in atomic mass units.
Explanation:
In simple words ;
mass number = protons + neutrons
Atomic number = no of protons
