How can you tell the number of protons and neutrons in its nucleus?

The number of protons in an atomic nucleus is indicated by the atomic number, which is unique to each element and can be found on the Periodic Table. To determine the number of neutrons, subtract the atomic number from the Atomic Mass (rounded to the nearest whole number). For example, if an element has an atomic number of 6 (carbon) and an atomic mass of approximately 12, it has 6 protons and 6 neutrons (12 - 6 = 6).