What does the atomic mass come from on the periodic table

Explanation: Atomic Mass is the mass of the atom. It is usually expressed in kilograms. It is almost equal to the sum of the number of protons and neutrons present in the atom.

The protons and neutrons of an atom are present in the nucleus itself and electrons are revolving around the nucleus.

In the periodic table, the elements are arranged according to their atomic properties. Atomic mass or mass number is written on the upper left side and atomic number is written on the lower right hand side.