Question

Why are atomic numbers and atomic mass numbers always whole numbers?

Answer 1

Atomic number refers to the number of electrons or protons present in an atom while atomic mass is defined as the total number of protons and neutrons in an atom. Since, the resultant of atomic numbers and atomic mass numbers are numbers, these are always natural numbers (not whole numbers).

NOTE: Whole numbers start with zero, while natural numbers start with one. Since, an atom that exists can neither have atomic number nor atomic mass number as zero, therefore, it cannot be said that the atomic numbers and atomic mass numbers are whole numbers. However, it can be said that atomic numbers and atomic mass numbers are natural numbers.