Question

question 2. what is the correct formula for the ionic compound formed between the chromium(iii) ion and the sulfide ion? crs cr₂s₃ cr₃s crs₂

Explanation:

Step1: Identify ion charges

Chromium(III) ion: $\text{Cr}^{3+}$ (the III indicates +3 charge).
Sulfide ion: $\text{S}^{2-}$ (sulfide is $\text{S}^{2-}$ from sulfur's -2 charge in ionic compounds).

Step2: Apply crisscross method

To balance charges, the magnitude of each ion's charge becomes the subscript of the other ion.

• Charge of $\text{Cr}^{3+}$ (3) becomes subscript of $\text{S}$.
• Charge of $\text{S}^{2-}$ (2) becomes subscript of $\text{Cr}$.

So, $\text{Cr}_2\text{S}_3$ (since $2\times(+3) + 3\times(-2) = 6 - 6 = 0$, charge is balanced).

Answer:

$\boldsymbol{\text{Cr}_2\text{S}_3}$ (corresponding to the option $\text{Cr}_2\text{S}_3$)