Question

what is the formula for chromium(iii) oxide? what is the formula for chromium(ii) sulfide? what is the formula for cobalt(iii) bromide? use the references to access important values if needed for this question.

Explanation:

Step1: Determine ion charges

Chromium(III) has a charge of +3 ($Cr^{3 +}$), oxygen has a charge of - 2 ($O^{2-}$). To balance the charges, we need 2 chromium ions and 3 oxygen ions.

Step2: Write the formula

The formula for chromium(III) oxide is $Cr_{2}O_{3}$.

Step3: Determine ion charges for chromium(II) sulfide

Chromium(II) has a charge of +2 ($Cr^{2+}$), sulfur has a charge of - 2 ($S^{2 -}$). The charges balance 1:1.

Step4: Write the formula

The formula for chromium(II) sulfide is $CrS$.

Step5: Determine ion charges for cobalt(III) bromide

Cobalt(III) has a charge of +3 ($Co^{3+}$), bromine has a charge of - 1 ($Br^{-}$). To balance the charges, we need 1 cobalt ion and 3 bromine ions.

Step6: Write the formula

The formula for cobalt(III) bromide is $CoBr_{3}$.

Answer:

Chromium(III) oxide: $Cr_{2}O_{3}$
Chromium(II) sulfide: $CrS$
Cobalt(III) bromide: $CoBr_{3}$