Question

Atomic mass of most of the elements is fractional. This is because of :

• A. mass is due to the sum of masses of p,n,e in it which are fractional
• B. average atomic mass of different isotopes of elements
• C. mass of ${}^{12}C$ is in fraction
• D. none of these

Answer 1

Answer: (B)

average atomic mass of different isotopes of elements

The atomic masses of most elements are fractional because they exist as a mixture of isotopes of different masses.
Most elements occur as a mixture of isotopes of different masses. The fractional atomic masses arise because of this mixture.