Question

Two elements $P$ and $Q$ combine to form a compound. If $P$ has $2$ and $Q$ has $6$ electrons in their outermost shell, what will be formula of the compound formed?

• A. $PQ$
• B. $P_{2}Q$
• C. $P_{2}Q_{3}$
• D. $PQ_{2}$

Answer 1

Answer: (A)

Valence electrons in $P$ is $2$; Valence electrons in $Q$ is $6$.
$P - 2e^{-} \rightarrow P^{2+} $
$Q +2e^{-} \rightarrow Q^{2-}$
Since both show a valency of $2$, the formula for the compound will be $PQ$.