Write a proper chemical name for each of the following ionic compounds: a. \(\mathrm{NaBr}\) b. \(\mathrm{CuCl}_{2}\) c. \(\mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{3}\) d. \(\left(\mathrm{NH}_{4}\right) 3 \mathrm{PO}_{4}\)

Binary ionic compounds are made up of two different elements: a metal (cation) and a non-metal (anion). Naming binary ionic compounds is fairly straightforward. The cation (positive ion) retains the name of the element, while the anion (negative ion) takes the element's name and modifies the ending to '-ide'. For example, in the compound \(\mathrm{NaBr}\), Sodium (Na) is a metal that typically forms a +1 cation, and Bromine (Br) as a non-metal forms an anion named Bromide. Together, these form the binary ionic compound known as Sodium Bromide.

It is important to note that this simple naming convention applies because Sodium forms only one type of cation. Other elements, particularly transition metals, can form cations with different charges, necessitating a different naming approach to reflect this variability.

Transition metals differ from other elements as they can form cations with varying charges. When naming transition metal ionic compounds, it is vital to determine the charge of the metal ion because the metal can exhibit more than one valence state. One uses Roman numerals in parentheses to indicate the cation's charge. For instance, \(\mathrm{CuCl}_{2}\) consists of Copper (Cu) and Chlorine (Cl). Copper can form multiple cations, but in this compound, the presence of two chloride ions, each with a -1 charge, signifies that the copper ion must have a +2 charge to balance the overall charge. Therefore, the proper name is Copper (II) Chloride, where 'II' denotes the +2 oxidation state of Copper.

A polyatomic ionic compound involves at least one ion that is a molecule made up of multiple atoms bonded together, which has a net charge, making it an ion. These ions can either be cations or anions. For example, \(\mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{3}\) contains Iron (Fe), which is a transition metal that forms the cation, and Nitrate \(\mathrm{NO}_{3}^{-}\), which is a polyatomic anion. Because iron can have more than one charge, we must specify it, and in this case, iron has a +3 charge to balance the three nitrate ions. Consequently, this compound is called Iron (III) Nitrate.

Understanding the naming of polyatomic ions is crucial since they are commonly found in chemistry. Some examples include \(\mathrm{SO}_{4}^{2-}\) which is called Sulfate, and \(\mathrm{NH}_{4}^{+}\) named Ammonium.

Chemical nomenclature involves a set of rules to generate systematic names for chemical compounds. The primary purpose is to clearly communicate which specific chemical species is being referenced in both written and oral communication. In ionic compounds, the cation name is stated first followed by the anion name. Binary ionic compounds end with '-ide'. If a compound includes a transition metal with multiple possible charges, a Roman numeral is used to indicate the specific charge the metal carries in the compound. When dealing with complex ions, such as polyatomic ions, one must recognize the individual ions based on their unique names and charges.

For multi-atom cations like Ammonium, in \(\left(\mathrm{NH}_{4}\right)_3 \mathrm{PO}_{4}\), the compound is named by stating the cation first, Ammonium, followed by the anion, Phosphate, resulting in Ammonium Phosphate. This systematic approach facilitates the learning and communication process in the field of chemistry.