Question

An element ‘X’ has a valency 1.

Write the chemical formula of its phosphide.

Answer 1

Phosphide (P) has a valency of 3 and element ‘X’ has a valency of 1.

So by using the criss-cross method formula of its phosphide is as follows: $$\begin{gathered} \mathrm{Symbol}\mathrm{X}\mathrm{P} \\ \searrow \swarrow \\ \mathrm{Valency}13 \end{gathered}$$

The chemical formula of its phosphide is ${\mathrm{X}}_3\mathrm{P}$.