Question

how are the number of protons represented in the periodic table?
atomic mass
atomic number
mass number
isotope

Explanation:

The atomic number of an element in the periodic table is defined as the number of protons in the nucleus of an atom of that element. Atomic mass is the average mass of atoms of an element considering isotopes. Mass number is the sum of protons and neutrons. An isotope is an atom of an element with the same number of protons but different number of neutrons.

Answer:

B. atomic number