Final answer:
Formulas for ionic compounds between calcium and polyatomic ions are derived by balancing the charges to ensure each compound is neutral. Examples include Ca(OH)2 for calcium hydroxide, CaCrO4 for calcium chromate, Ca3(PO4)2 for calcium phosphate, and Ca(CN)2 for calcium cyanide.
Step-by-step explanation:
When forming formulas for ionic compounds with polyatomic ions, it's important to balance the overall charges to ensure the compound is electrically neutral. For calcium (Ca2+), the formulas with polyatomic ions are:
- Calcium hydroxide: Ca(OH)2 (since hydroxide is OH−, two hydroxide ions are needed to balance one calcium ion)
- Calcium chromate: CaCrO4 (chromate is CrO42−, and since calcium has a 2+ charge, a one-to-one ratio is used)
- Calcium phosphate: Ca3(PO4)2 (with phosphate having a 3− charge, three calcium ions are required to balance two phosphate ions)
- Calcium cyanide: Ca(CN)2 (cyanide is CN−, requiring two cyanide ions to balance the charge of one calcium ion)
Use parentheses where required to ensure the correct stoichiometric ratios are represented in the formula.