As a kid learning chemistry in high school, I memorized some of the most common ions and their chemical formulae without exactly understanding their names. I guess I simply assumed they were arbitrary names.
This all changed a couple years ago when I started studying much more chemistry to understand the chemical composition and properties of any chemical that I would be working with in pyrotechnics. It was during this studying that I stumbled upon a naming pattern that may or may not have been explained to me, but either way, I was completely unaware of it.
While learning about some ions, particularly the negative ions known as anions, I saw that there are usually three suffixes that follow the name of an atom (typically a non-metal) to create an anion, which determine the chemical composition.
Here are some basic rules to help you understand the names of these anions.
The -ide Suffix
The -ide suffix means that the anion is simply composed of one type of atom whose name preceded the suffix. For example, sulfur becomes sulfide (S2-), phosphorous becomes phosphide (P3-), oxygen becomes oxide (O2-), and nitrogen becomes nitride (N3-).
Example Compounds
- Sodium Chloride: NaCl
- Iron Oxide:Fe2O3
- Tungsten Carbide:WC
- Potassium Iodide:KI
- Stannous Fluoride:SnF2
The -ite Suffix
The -ite suffix just means that some oxygen has been combined with the atom whose name comes before the suffix. Sulfur becomes sulfite (SO32-), phosphorous becomes phosphite (PO33-), and nitrogen becomes nitrite (NO2–).
Example Compounds
- Calcium Chlorite: Ca(ClO2)2
- Potassium Arsenite: KAsO3
- Sodium Sulfite: Na2SO3
- Sodium Nitrite: NaNO2
The -ate Suffix
The -ate suffix means that the ion has one more oxygen atom than the -ite suffix has. Sulfur becomes sulfate (SO42-), phosphorous becomes phosphate (PO43-), and nitrogen becomes nitrate (NO3–).
Example Compounds
- Potassium Chlorate: KClO3
- Sodium Iodate: NaIO3
- Magnesium Sulfate: MgSO4
- Potassium Nitrate: KNO3
The hypo- Prefix + the -ite Suffix
The hypo- prefix and -ite suffix are used to indicate that the ion has one less oxygen atom than the -ite ion. Chlorine forms the hypochlorite ion (ClO–).
Example Compounds
- Sodium Hypochlorite: NaClO
- Sodium Hypobromite: NaBrO
The per- Prefix + the -ate Suffix
The per- prefix and the -ate suffix mean that the ion has one or more oxygen atoms than the -ate ion. Chlorine makes the perchlorate ion in this case (ClO4–).
Example Compounds
- Ammonium Perchlorate: NH4ClO4
- Sodium Perbromate: NaBrO4
Chlorine is an atom that can have ions with all of the previously mentioned prefixes and suffixes: chloride (Cl–), hypochlorite (ClO–), chlorite (ClO2–), chlorate (ClO3–), and perchlorate (ClO4–).
Have you discovered any chemical patterns on your own?
Onward American 