Question

Write the systematic names for the following: (a) hypo \(\left(\mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}\right)\) (d) table salt ( \(\mathrm{NaCl}\) ) (b) laughing gas \(\left(\mathrm{N}_{2} \mathrm{O}\right.\) ) (e) milk of magnesia \(\left(\mathrm{Mg}(\mathrm{OH})_{2}\right)\) (c) alumina \(\left(\mathrm{Al}_{2} \mathrm{O}_{3}\right)\) (f) galena (PbS)

Short answer

The systematic names are: (a) Sodium thiosulfate, (d) Sodium chloride, (b) Dinitrogen monoxide, (e) Magnesium hydroxide, (c) Aluminum oxide, (f) Lead(II) sulfide.

Step-by-step solution

Systematic Name for Na2S2O3

To provide the systematic name for hypo \(\mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}\), recognize that this is a compound commonly known as sodium thiosulfate. The prefix 'hypo' and the suffix 'ite' traditionally indicate a specific oxyanion series in older nomenclature, but in systematic nomenclature, we name it based on its composition.

Systematic Name for NaCl

To name table salt, \(\mathrm{NaCl}\), note that it is composed of sodium ions and chloride ions. The systematic (IUPAC) name for this ionic compound is simply sodium chloride.

Systematic Name for N2O

Laughing gas or Nitrous oxide can be systematically named as dinitrogen monoxide. It is composed of two nitrogen atoms (di-) and one oxygen atom (mono-).

Systematic Name for Mg(OH)2

Milk of magnesia is a common name for \(\mathrm{Mg}(\mathrm{OH})_{2}\). The systematic name is magnesium hydroxide, where magnesium is the cation and hydroxide is the anion.

Systematic Name for Al2O3

Alumina is \(\mathrm{Al}_{2} \mathrm{O}_{3}\), which is composed of aluminum and oxygen. The IUPAC name is aluminum oxide.

Systematic Name for PbS

Galena is \(\mathrm{PbS}\), and in systematic terms, it is known as lead(II) sulfide. The (II) indicates the oxidation state of lead in the compound.

Key concepts

IUPAC Naming System

The International Union of Pure and Applied Chemistry (IUPAC) developed a systematic method for naming chemical compounds, which is essential for clear and precise scientific communication. This system provides a standard way to name compounds so that chemists around the world can easily communicate about them and understand their composition and structure.

When naming an inorganic compound, the IUPAC system starts with naming the cation (often a metal or hydrogen) followed by the anion (often a nonmetal or polyatomic ion). If the metal has more than one common oxidation state, Roman numerals in parentheses indicate this state. For molecules consisting of nonmetals, prefixes such as mono-, di-, tri-, etc., denote the number of atoms of each element present in the compound.

For students studying chemistry, becoming familiar with the IUPAC naming system is critical for interpreting the composition and properties of compounds and for ensuring that they can properly communicate their work.

Chemical Compound Names

Chemical compound names can come in various forms, including systematic names, common names, and formulas. Common names are often historical and may not provide clear information about the compound's makeup. For instance, 'table salt' is much less informative than its systematic name, sodium chloride, which tells us it consists of sodium and chloride ions.

To understand compound names deeply, one needs to recognize the patterns in how elements are named when combined. For binary compounds, the name usually ends in '-ide'. With polyatomic ions, the endings '-ate' or '-ite' are common, along with a prefix that helps to indicate the number of oxygen atoms.

Learning the various names helps students to connect familiar substances with their scientific designations, thereby enhancing their overall understanding of chemical nomenclature and its applications in real-world contexts.

Oxidation State

The oxidation state or oxidation number is a concept that describes the degree of oxidation of an atom in a chemical compound. It helps chemists understand electron transfer in reactions, especially redox (reduction-oxidation) processes. In IUPAC nomenclature, the oxidation state of a metal in a compound is indicated by a Roman numeral in parentheses following the element's name.

For example, in lead(II) sulfide, the '(II)' indicates that lead has an oxidation state of +2. Understanding how to assign oxidation states is fundamental when learning how to balance chemical equations and predict the products of reactions. It's crucial for students to recognize that oxidation states do not necessarily reflect actual charges on atoms in molecules but rather are a useful bookkeeping tool to track electron movement.

Inorganic Chemistry

Inorganic chemistry is the branch of chemistry concerned with the properties and behavior of inorganic compounds, which include metals, minerals, and organometallic (metal-carbon) compounds. It covers a wide range of substances not encompassed by organic compounds and includes many synthetic (e.g., plastics) and biological (e.g., proteins) materials.

An understanding of systematic nomenclature is incredibly valuable in inorganic chemistry because it allows chemists to infer a significant amount of information about the structure and reactivity of a compound just from its name. For students, building a foundation in inorganic chemistry involves learning about different groups of compounds, understanding periodic properties, and mastering basic concepts, including oxidation states and chemical nomenclature.