What is the atomic weight of helium ?

Vibhor27 Jul, 2022Education

Atomic weight, also called relative atomic mass, ratio of the average mass of a chemical element?s atoms to some standard. Since 1961 the standard unit of atomic mass has been one-twelfth the mass of an atom of the isotope carbon-12. An isotope is one of two or more species of atoms of the same chemical element that have different atomic mass numbers