Naming the ions is a fairly simple process once you have learned the rules behind it. The first aspect to consider is the charge of the ion under consideration (positive or negative) and whether it is composed of a single atom or several atoms. It is also necessary to assess whether the ion has more than one oxidation state (or oxidation number). Once you have found the answers to all these questions, following a few simple rules, it is possible to correctly name any type of ion.
Steps
Method 1 of 3: Monoatomic Ions with a Single Oxidation State
Step 1. Memorize the periodic table of elements
To learn how to name ions correctly, it is necessary to first study the names of all the elements from which they take shape. Memorize the entire periodic table of basic chemical elements to simplify the process of naming ions correctly.
If you have difficulty memorizing the periodic table of elements, you can consult it from time to time when you need it
Step 2. Remember to add the word "ion"
In order to distinguish an atom from an ion, the word "ion" must be inserted at the beginning of the name.
Step 3. In the case of positively charged ions, use the names of the chemical elements
The simplest ions to name are those that have a positive electric charge, composed of a single atom and with a single oxidation state. In this case the ions take the same name as the element they are made of.
- For example, the name of the "Na" element is "Sodium", so the name of its "Na +" ion will be "Sodium Ion".
- Ions that have a positive electric charge are also known as "cations".
Step 4. Add the suffix "-uro" in the case of negatively charged ions
Negatively charged monatomic ions with a single oxidation state are named using the root of the component name with the addition of the suffix "-uro".
- For example, the element name "Cl" is "Chlorine", so the name of its "Cl-" is "Ion Chloride". The name of the "F" element is "Fluoro", so the name of the relative "F-" ion will be "Ione Floruro". In the case of oxygen, "O2", the related "O2-" ion is called "superoxide".
- Ions that have a negative electric charge are also known as "anions".
Method 2 of 3: Monoatomic Ions with Multiple Oxidation States
Step 1. Learn to recognize ions that have multiple oxidation states
The oxidation number of an ion simply indicates the number of electrons it has gained or lost during the chemical reaction. Most transition metals, which are all grouped within the periodic table of chemical elements, have more than one oxidation state.
- The oxidation number of an ion is equivalent to its charge, which is represented by the number of electrons it possesses.
- Scandium and zinc are the only transition metals that have no more than one oxidation state.
Step 2. Use the Roman numbering system
The most commonly used method to indicate the oxidation state of an ion is to use its Roman numeral and enclose it in parentheses. This number also indicates the office.
- Again, as with any positively charged ion, you can continue to use the name of the element that composes it. For example, the "Fe2 +" ion is called the "Iron (II) ion".
- Transition metals do not have a negative charge, so you don't have to worry about using the "-uro" suffix.
Step 3. Familiarize yourself with the previous naming system as well
While the Roman numbering system is still known today, you may come across labels that still carry the old denomination of the ions. This system uses the suffix "-oso" to indicate iron ions with a lower positive charge and the suffix "-ico" to indicate iron ions with a higher positive charge.
- The suffixes "-oso" and "-ico" are relative to the name of the ions, therefore they do not give any indication of their charge, as does the new naming system based on Roman numerals. For example, using the old naming system, the Iron (II) ion is called "Ferrous Ion" because its positive charge is lower than that of the Iron (III) ion. Similarly, the Copper (I) ion is called the "Copper Ion" and the Copper (II) ion is called the "Copper Ion" since it has a higher positive charge than the Copper (I) ion.
- As can be deduced, this naming system is not suitable for ions that can take on more than two oxidation states, which is why it is preferable to adopt the naming system with Roman numerals.
Method 3 of 3: Polyatomic Ions
Step 1. Understand what polyatomic ions are
These are simply ions that are made up of several atoms of different elements. Polyatomic ions are different from ionic compounds, which occur when positively charged ions chemically bond to negatively charged ones.
As with ions, there is a naming system for ionic compounds as well
Step 2. Memorize the names of the most common polyatomic ions
Unfortunately, the polyatomic ion naming system is quite complex, so memorizing the ions that recur most frequently may be the best way to start studying it.
- The most common polyatomic ions include: bicarbonate ion (HCO3-), hydrogen sulphate ion or bisulfate ion (HSO4-), acetate ion (CH3CO2-), perchlorate ion (ClO4-), nitrate ion (NO3-), chlorate ion (ClO3-), nitrite ion (NO2-), chlorite ion (ClO2-), permanganate ion (MnO4-), hypochlorite ion (ClO-), cyanide ion (CN-), hydroxide ion (OH-), carbonate ion (CO32-), peroxide ion (O22-), sulphate ion (SO42-), chromate ion (CrO42-), sulphite ion (SO32-), dichromate ion (Cr2O72-), thiosulfate ion (S2O32-), hydrogen phosphate ion (HPO42-), phosphate ion (PO43-), arsenate ion (AsO43-) and borate ion (BO33-).
- The ammonium ion (NH4 +) is the only positively charged polyatomic ion (also called a polyatomic cation).
Step 3. Study the naming scheme of negatively charged polyatomic ions
Although this is a fairly complex system of rules, once you learn it, you will be able to name any polyatomic anion (the negatively charged ions made up of atoms of multiple chemical elements).
- Use the suffix "-ito" to indicate a low oxidation state. For example, in the case of the "NO2-" ion called nitrite ion.
- Use the suffix "-ate" to indicate a high oxidation state. For example, in the case of the "NO3-" ion called the nitrate ion.
- Use the prefix "hypo-" to indicate a very low oxidation state. For example, in the case of the "ClO-" ion called hypochlorite ion.
- Use the prefix "per-" to indicate a very high oxidation state. For example, or in the case of the "ClO4-" ion called perchlorate ion.
- There are exceptions to this naming scheme which are represented by hydroxide (OH-), cyanide (CN-) and peroxide (O22-) ions, which end with the suffixes "-ido" and "-uro" because in the past they were considered to be monatomic ions.
