Question

explain the need for a reference atom for atomic mass give some information about tow referenc atoms​

Answer 1

Answer:

Atomic mass is the is the sum of the electrons and the neutrons in the atom. Number of electrons is the atomic number. Hence to determine the atomic mass the reference of the atom is required. Example to find the atomic mass of atom magnesium Mg we need to know the atomic number of magnesium.

Answer 2

Answer:

A reference atom was required for expressing the relative mass of an atom. The hydrogen atom is the lightest was initially chosen as the reference atom. The relative mass of a hydrogen atom which has only one proton in its nucleus was accepted as one (1).