Question

Atomic masses of elements are usually fractional because:

• A. they are mixtures of isotopes
• B. they contain impurities of other atoms
• C. they are mixtures of isobars
• D. atomic masses cannot be weighed accurately

Answer 1

The correct option is A they are mixtures of isotopes

The atomic masses of most elements are fractional as most elements occur as a mixture of isotopes of different masses

Average$=\frac{Totalmassofallatoms}{Numberofatoms}$