Write the chemical formula for the compound formed by each pair of positive and negative ions.

Question

Write the chemical formula for the compound formed by each pair of positive and negative ions.

Write the chemical formula for the compound formed by each pair of positive and negative ions.

1.  Ba²+ and NO₃−:
2.  Al³+ and CO₃^2-:
3.  K⁺ and PO₄^3-:

Answer 1

Hello

You want the complete charge on the final molecule to be ZERO. To get the answer, 'SWAP and DROP' the superscripts with the charges; bring the superscripts to the other ion and place them as subscripts but DO not bring the charge along to the subscripts that you just swapped. And be sure to place the polyatomic ions in parentheses if you will need more than one of that ion.

1) Ba (NO₃)₂

2) Al₂(CO₃)₃ EX Note that for aluminum with charge of +3, the total charge is +3 X 2 = +6 and for CO3, the total charge is -2 X 3 = -6. and (+6 and -6 = 0 total charge for molecule)

3) K₃PO₄

Answer 2

We want to balance the charges for each ion that make up the compound.

1.) Ba²⁺ and NO₃^-. It will take 2 of the NO₃^- to balance the Ba²⁺ ---> Ba(NO₃)₂

2.) Al₃₊ and CO₃^2-. We need 2 of the Al³⁺ and 3 of the CO₃^2- ---> Al₂(CO₃)₃

3.) K⁺ and PO₄^3-. It will take 3 of the K⁺ for each PO₄^3- ---> K₃PO₄