Write formulas for the following compounds: (a) Calcium acetate (b) Iron(II) cyanide (c) Sodium dichromate (d) Chromium(III) sulfate (e) Mercury(II) perchlorate

Verified step by step guidance

1. Identify the ions involved in each compound. For example, calcium acetate involves the calcium ion (Ca^2+) and the acetate ion (CH3COO^-).
2. Determine the charge of each ion. Calcium has a +2 charge, acetate has a -1 charge, iron(II) has a +2 charge, cyanide has a -1 charge, etc.
3. Balance the total positive and negative charges to ensure the compound is electrically neutral. For instance, since calcium has a +2 charge and each acetate has a -1 charge, you need two acetate ions to balance one calcium ion.
4. Write the chemical formula by placing the cation first followed by the anion. Use subscripts to indicate the number of each ion needed to balance the charges.
5. For polyatomic ions that appear more than once in the formula, use parentheses to group them together before adding a subscript. For example, in calcium acetate, write it as Ca(CH3COO)2.

Key Concepts

Ionic Compounds

Ionic compounds are formed when metals react with nonmetals, resulting in the transfer of electrons. The metal loses electrons to become a positively charged cation, while the nonmetal gains electrons to become a negatively charged anion. The electrostatic attraction between these oppositely charged ions creates a stable compound. Understanding the formation of ionic compounds is essential for writing their chemical formulas.

Nomenclature of Coordination Compounds

Coordination compounds consist of a central metal atom bonded to surrounding molecules or ions called ligands. The nomenclature rules for these compounds involve identifying the oxidation state of the metal and naming the ligands appropriately. For example, in Iron(II) cyanide, the Roman numeral indicates the +2 oxidation state of iron, which is crucial for determining the correct formula.

Polyatomic Ions

Polyatomic ions are ions composed of two or more atoms that are covalently bonded and carry a net charge. Common examples include sulfate (SO4^2-) and perchlorate (ClO4^-). Recognizing these ions is vital for accurately writing the formulas of compounds that contain them, as they often dictate the overall charge balance in ionic compounds.