Any element can always be identified by its: atomic mass number of neutrons number of protons atomic number

Answer 1

This statement is a little confusing, but I will try to explain:

Each element has one atomic number, period. The atomic number is also the number of protons the atoms of this element have. For example, the oxygen atom has 8 protons, its atomic number is 8.

The atomic mass is the sum of the number of protons and neutrons of an atom. Atoms with the same atomic number but different masses are called isotopes. Hydrogen, for example, has 3 isotopes, with masses of 1, 2 and 3, respectively.

The mass, as written in the periodic table is an weighted average, relative to its abundance, of the atomic mass of each isotope of the element.

Answer 2

Each element has a unique number which defines it. This number is the atomic number. But what does the atomic number really represent? Look that up and you will have a complete answer.