Question

12c isotope contains how many particles why it taken as reference standard and must give example.​

Answer 1

One atomic mass unit(amu) is equal to 1/12 of the mass of an atom of C12 isotope

Since mass of 1atom of C12 is 1.99×10^-23 g

1/12 th part of mass of 1 atom = 1.99× 10 ^-23 /12

= 1.67 × 10^ -24 = 1/Na ( 1Na = 6.02× 10^-23)

It is taken as reference standard as it indicate how many times the mass of one atom is heavier in comparison to 1/12 part of mass of one atom of C12. It indicate only relative atomic mass not the actual mass