Question

(a) Name the element used as a standard for atomic mass scale.
(b) Which particular atom of the above element is used for this purpose ?
(c) What value has been given to the mass of this reference atom ?

Answer 1

(a) Carbon is used as a standard in the atomic mass scale.
(b) Carbon-12 atom is particularly used as a standard in the atomic mass scale.
(c) Carbon-12 atom has been given a mass of exactly 12 units (${}_6{}^{12}\mathrm{C}$ has six protons and six neutrons).