Question

Element $X$ is a metal with a valency 2. Element $Y$ is a non-metal with a valency 3.

The balance equations to show how $X$ and $Y$ form ions is :

• A. $X-2e^{-}\to X^{2+}$
• B. $Y+2e^{-}\to Y^{2-}$
• C. $X-e^{-}\to X^{+}$
• D. None of these

Answer 1

Answer: (A)

$X-2e^{-}\to X^{2+}$

Element $X$ is a metal with valency 2 that means it is a reducing agent and can release 2 electrons but cannot accept while $Y$ is a non-metal with a valency 3 that means it can accept 3 electrons and the stable ion is $Y^{3-}$.

So the balance equation for formation of ion is :

$X-2e^{-}\to X^{2+}$

Option (B) is showing addition of two electrons that will not be able to form stable ion $Y^{3-}$. Metal ion $X^{+}$ is also unstable.