5) each element is unique and different from other elements because of the number of protons in the nuclei of its atoms. which of the following indicates the number of protons in an atom's nucleus? a) atomic mass b) atomic weight c) atomic number d) mass weight e) mass number

the answer is c

Explanation:

The number of protons within the nucleus of a given atom is equal to the atomic number of the corresponding element, which can be found on the periodic table. For example, the atomic number of helium is two. Therefore, the number of protons is also two.

there are two significant figures.