Question

what is the formula for calcium sulfide? what is the formula for aluminum chloride? what is the formula for magnesium oxide?

Explanation:

Step1: Determine calcium and sulfide ions

Calcium ion is $Ca^{2 + }$, sulfide ion is $S^{2 - }$. To form a neutral compound, the charges must balance. Since the magnitudes of the charges are the same, the ratio is 1:1.

Step2: Write calcium sulfide formula

The formula for calcium sulfide is $CaS$.

Step3: Determine aluminum and chloride ions

Aluminum ion is $Al^{3+}$, chloride ion is $Cl^{-}$. To balance the charges, we need 3 chloride ions for 1 aluminum ion.

Step4: Write aluminum chloride formula

The formula for aluminum chloride is $AlCl_{3}$.

Step5: Determine magnesium and oxide ions

Magnesium ion is $Mg^{2+}$, oxide ion is $O^{2 - }$. Since the magnitudes of the charges are the same, the ratio is 1:1.

Step6: Write magnesium oxide formula

The formula for magnesium oxide is $MgO$.

Answer:

Calcium sulfide: $CaS$
Aluminum chloride: $AlCl_{3}$
Magnesium oxide: $MgO$