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 give fractional masses

Answer 1

Answer: (A), (C)

they have isotopes
their isotopes have different masses

Elements have non integral atomic masses because isotopes are having different masses and are occur in the nature in different proportion.

Eg. $Cl;z=17$ and $A=35$ and $37$. They are present in the ratio $3:1$.

$\therefore \frac{3\times 35+1\times 37}{4}=35.5$ (A)

Hence, options A & C are correct.