Question

Write the Chemical formula of Arsenic sulphide.

Answer 1

When writing the formula, the positive atom or ion comes first followed by the name of the negative ion.

Arsenic sulphide consists of Arsenic ion and sulphide ion i.e. ${\mathrm{As}}^{+3}$ and ${\mathrm{S}}^{-2}$, which have a charge of +3 and -2 respectively.

Symbol $\mathrm{As}$ $\mathrm{S}$

Charge +3 -2

On cross-multiplication and balancing the charge, we get the formula as ${\mathrm{As}}_2{\mathrm{S}}_3$.

Thus, the chemical formula of Arsenic sulphide is ${\mathbf{As}}_{\mathbf{2}}{\mathbf{S}}_{\mathbf{3}}$.