Answer:
Boron Carbonate; B₂(CO₃)₃
Explanation:
For names, carbonide does not exist; that rules out the first option. Carbide refers to just a carbon atom, not carbon and oxygen as in the polyatomic ion carbonate. That rids us of the third option. We are left with boron carbonate with the formula BCO or boron carbonate with the formula B₂(CO₃)₃.
Recall the carbonate polyatomic ion's formula: CO₃²⁻
Thus BCO cannot be the formula.
Option 4 is your answer, Boron Carbonate; B₂(CO₃)₃.
To further check your answer, observe the oxidation states of boron and the polyatomic ion carbonate. Boron can exist in oxidation states of either 2+ or 3+, and carbonate is only 2-; in this formula, boron will exhibit a 3+ state to balance out with carbonate.
2x3+ = 6+; 3x2- = 6-
6+ + 6- = 0; balanced
