New version page

UGA CHEM 1110 - Ionic Compounds Lecture 3 - Naming Ionic Compounds

This preview shows page 1-2 out of 5 pages.

View Full Document
View Full Document

End of preview. Want to read all 5 pages?

Upload your study docs or become a GradeBuddy member to access this document.

View Full Document
Unformatted text preview:

Naming Ionic Compounds 1Preview The lectures in this unit cover the formation of ions and ionic compounds, properties of ions and nomenclature of ionic compounds. This lecture covers nomenclature (naming) of ionic compounds. Nomenclature of Ionic Compounds I. Naming Ionic Compounds When communicating information about ionic compounds it is often more convenient to refer to the compound by name instead of stating the formula. In many cases on product and medicinal packaging, compounds are referred to by name only instead of formula (and vice versa); so knowing how to convert between the name and the formula of an ionic compound is important! Remember that when giving an ionic formula, the cation (or + ion) is always listed first. We also follow this pattern both in naming ionic compounds: first we name the cation, and then we name the anion. Naming ionic compounds is simple once you know how to name individual cations and anions. A. Naming the Cation In our last lectures we discovered three different types of cations: main group cations, polyatomic ions, and transition metal cations. Each of these has different naming rules. It is important to be aware of which type of cation we are naming so we can follow the correct rules. For main group elements the name of the cation is the name of the element which makes the cation. So a sodium cation in a compound is referred to as ‘sodium’. We do not need to say ‘sodium ion’ because it is understood that in a compound, sodium is always an ion. We don’t need to say ‘sodium 1+’ because it is understood that if it is an ion, sodium always has a 1+ charge. The fact that it is an ion and the fact that it has a particular charge are implicit in the name. We need only name the element that formed the ion. For polyatomic ions the name of the cation is the name of the polyatomic ion listed in your chart. So an ammonium cation is just referred to as ‘ammonium’. We do not need to say ‘ammonium ion’ because it’s understood that ammonium is the name of an ion. We do not need to indicate any formula information because we understand every time that we see the name of the polyatomic ion that it has a specific formula. We also understand that it has a defined charge. Again, the fact that it is an ion with a specific formula and a given charge is implicit in the name. We need only give the name of the polyatomic ion. Transition metal ions are subject to two different naming rules. This comes from two different systems in place for helping the reader understand what the charge of the transition metal ion is. The reason for this is because although we understand that the metal is a cation, we do not know implicitly what the charge of that ion is because transition metals can have moreNaming Ionic Compounds 2than one ion type! As both of these naming methods are in common use (albeit in different circles) you should be familiar with the basics of both sets of naming rules. In the IUPAC (International Union for Pure and Applied Chemistry) rules for transition metal cations, the name of the cation is the name of the element which makes the cation PLUS a Roman numeral to indicate charge in parentheses. For instance, the Fe3+ ion is referred to as iron (III). Co2+ is named cobalt (II). Cu+ is copper (I). From a scientific point of view the IUPAC rules are universal, standardized, easy to follow and require little memorization. Chemical scientists use this system almost exclusively. The classical (Latin) naming rules give each different transition metal ion its own name. For instance, the Fe3+ ion is referred to as ferric, while the Fe2+ is named ferrous. Cu+ is cuprous, while the Cu2+ is cupric. A partial list of classical transition metal names alongside IUPAC names is given to the right. While the scientific community generally views classical names as an outdated model, the medical community still uses them almost exclusively and you will see these names on IV bags as well as over the counter supplements. For example iron supplements at the store are sold as “ferrous sulfate”. Note that in two cases the IUPAC name and the classical name are the same: silver is only stable as a +1 ion and zinc is only stable as a +2 ion, so we do not specify charges for these two ions. I will not test you on the classical (Latin) naming rules. You do not have to memorize them. I am including classical naming information only so you have exposure to it because the medical community does still use these. I WILL test you on the IUPAC naming rules. IUPAC name Transition metal cation Classical name silver Ag+ silver cobalt (II) Co2+ cobaltous cobalt (III) Co3+ cobaltic chromium (II) Cr2+ chromous chromium (III) Cr3+ chromic copper (I) Cu+ cuprous copper (II) Cu2+ cupric iron (II) Fe2+ ferrous iron (III) Fe3+ ferric manganese (II) Mn2+ manganous manganese (III) Mn3+ manganic nickel (II) Ni2+ nickelous nickel (III) Ni3+ nickelic lead (II) Pb2+ plumbous lead (IV) Pb4+ plumbic tin (II) Sn2+ stannous tin (IV) Sn4+ stannic zinc Zn2+ zincNaming Ionic Compounds 3--------------------------------------------------------------------------------------------------------------------- Take a minute to complete your Ionic Compounds Worksheet section VI. This has you provide names for various cations as per the naming rules above: as well as provide the cation symbol for cations which have been named. It is a good idea to practice this while it is fresh!! --------------------------------------------------------------------------------------------------------------------- B. Naming the Anion In our last lectures we discovered two different types of anions: main group anions and polyatomic ions. Each of these types has different naming rules. It is important to be aware of which type of anion we are naming so we can follow the correct rules. For main group elements the name of the anion is the name of the element which makes the cation, with an –ide suffix. So an oxygen anion in a compound is referred to as ‘oxide’ and a fluorine anion in a compound is referred to as ‘fluoride’. We do not need to say ‘oxide ion’ because the name oxide indicates it is the oxygen ion. We do not need to say oxide -2 because it is understood that if it is in an ionic compound, oxygen is always a -2 ion. The fact that it is an ion and the fact that it has a given charge are implicit in the


View Full Document
Loading Unlocking...
Login

Join to view Ionic Compounds Lecture 3 - Naming Ionic Compounds and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Ionic Compounds Lecture 3 - Naming Ionic Compounds and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?