Answer:
atomic number
mass number
isotope
Step-by-step explanation:
1 . Atomic number ,For neutral atom , the value for atomic number equals the number of protons , and it helps to define the identify of an element .
2. Mass number , For neutral atom , the summation of the number of protons and the number of neutrons , together gives the value of mass number .
3. Isotopes , are the substance , where the in a specific element , the number of neutrons are different .