Problem 36 - Chemistry: An Atoms-Focused Approach

Question

What are the names of the following ionic compounds? (a) \(\mathrm{Mg}\left(\mathrm{ClO}_{4}\right)_{2} ;\) (b) \(\mathrm{NH}_{4} \mathrm{NO}_{3} ;(\mathrm{c}) \mathrm{Cu}\left(\mathrm{CH}_{3} \mathrm{COO}\right)_{2}\) (d) \(\mathrm{K}_{2} \mathrm{SO}_{3}\)

Step-by-Step Solution

Answer

Question: Provide the names of the following ionic compounds: a) \(\mathrm{Mg}\left(\mathrm{ClO}_{4}\right)_{2}\) b) \(\mathrm{NH}_{4}\mathrm{NO}_{3}\) c) \(\mathrm{Cu}\left(\mathrm{CH}_{3}\mathrm{COO}\right)_{2}\) d) \(\mathrm{K}_{2} \mathrm{SO}_{3}\) Answer: a) Magnesium Perchlorate b) Ammonium Nitrate c) Copper(II) Acetate d) Potassium Sulfite

Step 1: Identify the ions present in each compound

Look at the chemical formulas for the compounds and identify the ions present in them. (a) \(\mathrm{Mg}\left(\mathrm{ClO}_{4}\right)_{2}\): The ions present are Mg\(^{2+}\) and \(\mathrm{ClO}_{4}^{-}\). (b) \(\mathrm{NH}_{4}\mathrm{NO}_{3}\): The ions present are \(\mathrm{NH}_{4}^{+}\) and \(\mathrm{NO}_{3}^{-}\). (c) \(\mathrm{Cu}\left(\mathrm{CH}_{3}\mathrm{COO}\right)_{2}\): The ions present are Cu\(^{2+}\) and \(\mathrm{CH}_3\mathrm{COO}^{-}\). (d) \(\mathrm{K}_{2} \mathrm{SO}_{3}\): The ions present are K\(^{+}\) and \(\mathrm{SO}_{3}^{2-}\).

Step 2: Name the ions present in each compound

Now, we'll assign names to the ions we identified in Step 1. (a) Mg\(^{2+}\) is called Magnesium ion and \(\mathrm{ClO}_{4}^{-}\) is called Perchlorate ion. (b) \(\mathrm{NH}_{4}^{+}\) is called Ammonium ion and \(\mathrm{NO}_{3}^{-}\) is called Nitrate ion. (c) Cu\(^{2+}\) is called Copper(II) ion (the II in this case refers to the charge of the ion) and \(\mathrm{CH}_3\mathrm{COO}^{-}\) is called Acetate ion. (d) K\(^{+}\) is called Potassium ion and \(\mathrm{SO}_{3}^{2-}\) is called Sulfite ion.

Step 3: Combine the ion names to form the compound name

Finally, we'll join the ion names to form the name of each compound. [a] \(\mathrm{Mg}\left(\mathrm{ClO}_{4}\right)_2\): Magnesium Perchlorate [b] \(\mathrm{NH}_{4}\mathrm{NO}_{3}\): Ammonium Nitrate [c] \(\mathrm{Cu}\left(\mathrm{CH}_{3}\mathrm{COO}\right)_{2}\): Copper(II) Acetate [d] \(\mathrm{K}_{2} \mathrm{SO}_{3}\): Potassium Sulfite

Key Concepts

Chemical Nomenclature

Chemical nomenclature is the system used to name chemical substances. For ionic compounds, the name consists of two parts: the name of the cation (positively charged ion) and the name of the anion (negatively charged ion).

• The cation is named first, using the element name.
• If the cation can have more than one charge, as is common with transition metals, we indicate its charge with a roman numeral in parentheses. For example, Copper(II) signifies a copper ion with a charge of +2.
• The anion is named second, usually ending in "-ide," "-ite," or "-ate" depending on its type and composition.

The systematic approach ensures that each compound has a distinct and understandable name, which allows chemists around the world to communicate unambiguously about compounds.

Polyatomic Ions

Polyatomic ions are groups of atoms that behave as a unit and carry a collective charge. Unlike monoatomic ions which consist of single atoms, polyatomic ions often consist of multiple elements bound together, making them crucial in forming various ionic compounds.Some common polyatomic ions include:

• Ammonium ion ( \(\mathrm{NH}_4^{+}\)
  )
• Nitrate ion ( \(\mathrm{NO}_3^{-}\)
  )
• Acetate ion ( \(\mathrm{CH}_3\mathrm{COO}^{-}\)
  )
• Perchlorate ion ( \(\mathrm{ClO}_4^{-}\)
  )
• Sulfite ion ( \(\mathrm{SO}_3^{2-}\)
  )

Understanding these ions can make naming compounds easier, as you can quickly recognize them and assign their correct names when they occur in a compound.

Chemical Formulas

Chemical formulas represent the composition of a compound, indicating the types and numbers of atoms involved. In ionic compounds, the chemical formula balances the total positive and negative charges to achieve a net charge of zero.In a chemical formula:

• The cation is written first, followed by the anion.
• The subscript numbers indicate the number of each ion needed to balance the charges. For instance, in \(\mathrm{Mg(ClO_4)_2}\), two perchlorate ions are needed to balance the +2 charge from one magnesium ion.

Interpreting and writing chemical formulas correctly is essential for understanding the structure and properties of ionic compounds.

Ions Naming

Naming ions is a foundational skill in understanding chemical nomenclature. Ions can either be cations or anions, depending on whether they lose or gain electrons.In naming:- **Cations**: Generally named after the element unless they have multiple oxidation states. For example, \(\mathrm{Ca^{2+}}\) is called calcium ion, but \(\mathrm{Fe^{3+}}\) is ferric ion or iron(III) ion. - **Anions**: Typically end in "-ide" for simple monoatomic anions, such as chloride \(\mathrm{Cl^{-}}\), or "-ate" and "-ite" for oxyanions, depending on the number of oxygen atoms.Mastering ion naming allows one to deduce the chemical names of compounds and write them accurately based on their formulas.