As you move from right to left on the periodic table, what happens to the number of protons and neutrons in atoms?

As you move across a period, the atomic mass increases because the atomic number also increases. When the atomic number increases, this means that there are more protons and neutrons that add to the atomic mass of an atom. The atomic mass for any given atom mainly comes from the mass of the protons and neutrons

it might be late but honestly my fault for not checking any earlyer