Question

(b) Many elements have fractional atomic masses. This is because:
(a) the mass of the atom is itself fractional..
(b) atomic masses are average masses of isobars.
(c) atomic masses are average masses of isotopes.
(d) atomic masses are average masses of isotopes proportional to their relative abundance.
​

Answer 1

Answer:

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

Answer 2

(d) atomic masses are average masses of isotopes proportional to their relative abundance.