Question

write the chemical formula for the compound formed by each pair of positive and negative ions.
ba²⁺ and no₃⁻:
al³⁺ and co₃²⁻:
k⁺ and po₄³⁻:

Explanation:

Step1: Balance charges for Ba²⁺ and NO₃⁻

To balance the +2 charge of Ba²⁺, we need 2 NO₃⁻ ions. So the formula is Ba(NO₃)₂.

Step2: Balance charges for Al³⁺ and CO₃²⁻

The +3 charge of Al³⁺ and - 2 charge of CO₃²⁻. We find the least - common multiple of 3 and 2 which is 6. So we need 2 Al³⁺ and 3 CO₃²⁻. The formula is Al₂(CO₃)₃.

Step3: Balance charges for K⁺ and PO₄³⁻

To balance the - 3 charge of PO₄³⁻, we need 3 K⁺ ions. So the formula is K₃PO₄.

Answer:

Ba(NO₃)₂
Al₂(CO₃)₃
K₃PO₄