Question

_______ is the number of protons in the nucleus of an atom, which identifies what the element is.

Answer 1

Answer:

atomic number

mass number

 isotope

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 .