Question

Many elements have non-integral atomic masses because
A. They have isotopes
B. Their isotopes have non-integral masses
C. Their isotopes have different masses
D. The constituents , neutrons , protons and electrons, combine to given fractional masses

Answer 1

Correct Answer - A::C
Because they have isotopes with different masses. Their average atomic mass is the weighted mean of their presence in nature , e.g., `Cl^35` and `Cl^37` are present in ratio 3:1.
So, `A=(35xx3+37xx1)/4 =35.5`