Many elements have non-integral atomic masses because

Options

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

A, C

Explanation

because they have isotopes with different masses. Their average atomic mass is the 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`