Chemistry: Nomenclature

Knowing your nomenclature is a vital part of chemistry, as it makes writing chemical formulas and equations much easier to write and read. Without knowing chemical nomenclature, many of your equations will turn out wrong. But first, what is nomenclature?

In its broad definition, nomenclature is simply a way/rule of naming a collection of things. Within chemistry, there is nomenclature for a variety of categories. 

Ionic Compounds 

• An ionic compound is composed of a metal (positive part) and a nonmetal (negative part) and are formed to form an ionic compound, in which the positive part (the metal) is written first within the equation. 

• To write an equation, simply swatch the charges of the metal and non metal and write it as the subscripts. 

• Ex.) H2O (H has plus 1 charge, O has 2 minus charge, H has a 2 subscript, O has 1 as a  subscript)

• Ex.) CaF2 (Ca has 2 plus charge, F has 1 minus charge, Ca has 1 as a subscript, F has a 2 subscript)

  • If the subscript is 1, it is not written in

• When reading ionic compounds, simply say the name of the first element, then change the ending of the second element to ide. 

Transitional Metals

Transition metals (the elements within the “d” group on the periodic table) can have multiple charges, and thus different latin names for their different forms. 

• For elements like Silver, (Ag+1) Nickel, (Ni+2) or Gold (Au+3)they are simply referred to by their element name and ion followed after. 

• However, for elements such as Cobalt or Lead, there is a nomenclature assigned to them.

Copper

Copper I (Cuprous) → Cu+1

Copper II (Cupric) → Cu+2

Chromium

Chromium II  (Chromous) →Cr+2

Chromium III (Chromic) → Cu+3

Lead

Lead II (Plumbous) →Pb+2

Lead IV (Plumbic) → Pb+4

Tin

Tin II (Stannous) →Sn+2

Tin IV (Stannic) → Sn+4

Cobalt

Cobalt II (Cobaltous) → Co+2

Cobalt III (Cobaltic) → Cu+3

2 Non Metals

• Not all chemical formulas are a metal or a non metal. Sometimes, they can simply be multiple non metals. These are called covalent compounds. 

• When naming these compounds, they follow a different step of nomenclature rules. 

  • Prefixes are used for covalent compounds.

• Depending upon how many elements are within a compound, you place the prefix first, the first compound name, and if there is multiple of the second element, place the prefix, then change the ending of the element to ide. 

• Ex.) FO5→Fluorine Pentoxide

• Ex.)  S2F7→ DiSulfur Heptafluoride

1. mono

2. di

3. tri

4. tetra

5. penta

6. hexa

7. hepta

8. octa

9. nona

10. deca