Question

An element $A$ decays into element $C$ by a two step process
$A\to B{+}_{2}H{e}^4;B\to C+2e^{-}$Then

• A. A and C are isotopes
• B. A and C are isobars
• C. A and B are isotopes
• D. A and B are isobars

Answer 1

Answer: (A)

From equation (ii), $B$ has $2$ units of charge more than $C$.
From equation (i), $A$ loses $2$ units of charge by emission of alpha particle.
Hence, $A$ and $C$ are isotopes as their charge number is same