Problem 43 - General Chemistry: Principles and Modern Applications

Question

Give an appropriate name to each of the following compounds: (a) \(\mathrm{ZnS} ;\) (b) \(\mathrm{KHSO}_{3} ;\) (c) \(\mathrm{K}_{2} \mathrm{S}_{2} \mathrm{O}_{3} ;\) (d) \(\mathrm{SF}_{4}\).

Step-by-Step Solution

Answer

The names for the respective compounds are: (a) Zinc Sulfide, (b) Potassium Hydrogen Sulfite, (c) Potassium Thiosulfate, (d) Sulfur Tetrafluoride

Step 1: Identify the elements in the compound

To name a chemical compound, one needs to identify the individual elements from their chemical symbol. For example, for compound (a) \(Zn\) stands for Zinc and \(S\) stands for Sulfur.

Step 2: Apply naming guidelines

For ionic compounds, the metal ion keeps its name (in this case, Zinc) and the nonmetal ion takes its root and attaches '-ide' at the end. So, \(ZnS\) is named Zinc Sulfide.

Step 3: Repeat Steps 1 and 2 for the remaining compounds

Repeat the same process for each compound. For compound (b) \(K\) stands for Potassium, \(H\) for Hydrogen, \(S\) for Sulfur and \(O\) for oxygen. This compound is named as Potassium Hydrogen Sulfite. Similarly, (c)\(K_{2}S_{2}O_{3}\) is named Potassium Thiosulfate and (d) \(SF_{4}\) is named Sulfur Tetrafluoride.

Key Concepts

Chemical Nomenclature

Chemical nomenclature is the system used to name chemical compounds. Understanding this system is crucial for correctly identifying different substances. Generally, chemical nomenclature falls into two main categories: naming ionic compounds and naming molecular compounds.

This naming system ensures that every compound has a unique name, derived from rules set by scientific guidelines. The process involves recognizing the components of a compound and applying specific naming conventions. These conventions reflect the type of elements involved, their quantities, and their structural differences. By following these guidelines, chemists can communicate effectively and avoid confusion when discussing chemical substances.

Ionic Compounds

Ionic compounds consist of positive (cations) and negative (anions) ions that are bound together through ionic bonds. The naming of ionic compounds follows a straightforward rule: the name of the cation is stated first, followed by the name of the anion.

For the cation, which is typically a metal, its name remains unchanged. For example, sodium in sodium chloride. In the case of the anion, which is usually a non-metal, the suffix '-ide' is appended to its root name, as seen with chloride in sodium chloride.

• For example, in the compound ZnS, Zinc (Zn) is the cation, and thus retains its name. Sulfur (S), the anion, changes to sulfide.
• This leads to the complete name: Zinc Sulfide.

Understanding this naming structure is essential for identifying the correct names of ionic compounds.

Molecular Compounds

Molecular compounds differ from ionic compounds as they are formed by atoms sharing electrons through covalent bonds. These compounds are typically composed of non-metal elements.

When naming molecular compounds, prefixes are used to indicate the number of atoms present. The first element in the formula retains its elemental name, while the second element's name is modified to end in '-ide', similar to ionic compounds. The prefix 'mono-' is used for one atom, 'di-' for two, 'tri-' for three, and so on.

• For example, SF4 is a molecular compound with one sulfur atom and four fluorine atoms.
• The name becomes Sulfur Tetrafluoride, with 'tetra-' indicating the four fluorine atoms.

Using prefixes allows us to convey detailed information about a compound's structure directly within its name.

IUPAC Naming

The International Union of Pure and Applied Chemistry (IUPAC) provides a systematic set of guidelines for naming chemical compounds, ensuring a standardized approach that is recognized globally. IUPAC naming takes into account the types of bonds, functional groups, and elements involved in a compound.

This system adopts specific rules for arranging words and numbers to uniformly describe the structure of molecules. It incorporates prefixes, root names, and suffixes to precisely convey the chemical's composition. For students, understanding IUPAC naming is fundamental to studying chemistry, as it reflects the universal language used by chemists around the world.

Getting familiar with IUPAC guidelines helps in predicting the possible structure and functionality of compounds, thus bridging the gap between chemical formulae and compound properties.