Many elements have non-integral atomic masses because\

Question

Professor PC Thomas Classes · Answer

(a,c) : Isotopes have same atomic number but different mass numbers. The average atomic mass is the weighed mean of their occurrence in nature. $\mathrm{Cl}^{35}$ and $\mathrm{Cl}^{37}$ occur in nature in the ratio of $3: 1$ so the average atomic mass of Cl is given as\ $\frac{35 	imes 3+37 	imes 1}{4}=35.5$\