Naming Chemical Formula

   Naming Binary Chemical Formula

Many chemical compound names consist of two words. The words are derived from the ions that combine to form the compound. Those compounds that consist of only 2 elements are called binary compounds. Some elements form more than one covalent compound with another element. For example, 2 compounds made of sulphur/sulfur and oxygen could be: SO2 and SO3.

The names of binary compounds usually end with “-ide”. This is from the second combining element. For example: bromine – bromide or sulphur/sulfur – sulphide/sulfide and so forth. Binary compounds can be either ionic or covalent.

Covalent binary compounds (e.g. N2O) are named by following these steps:

 

1. The first word of the name is made up of (a) a prefix indicating the number of atoms of the first element appearing in the formula, if more than one; and (b) the name of the first element in the formula (e.g, di-nitrogen, for “N2” of N2O).

2. The second word of the name is made up of (a) a prefix indicating the number of atoms of the second element appearing in the formula, if more than one compound of these two elements exists: (b) the root of the name of the second element and (c) the suffix “- ide”, which means that only the two elements named are present (e.g. mono-oxide for “O” of N2O).

Thus, the name of the compound with the chemical formula, N2O is dinitrogen monoxide.

The Prefixes:

               mono – meaning one 

di – meaning two

tri – meaning three 

tetra – meaning four 

pent – meaning five

1. The prefix ‘mono’ can be omitted if only one of the combining elements is made of one atom. For example,

N2O - Could either be dinitrogen monoxide or dinitrogen oxide.

CO - Will be carbon monoxide and not carbon oxide because carbon and oxygen are both one (mono).

2. A few negative polyatomic ions (ions made up of two or more atoms) have names with an “-ide” suffix, for example, hydroxide ion, OH- and cyanide ion, CN-. Thus, the compounds LiOH and KCN are named lithium hydroxide and potassium cyanide, respectively.

 

Compounds formed with either of these polyatomic ions are not binary.

                                                                                                              These and a number of other such ionic compounds are called ternary compounds, meaning compounds consisting of three elements.

Common Compounds

Chemical Formula	Name
NO	nitrogen oxide
NO2	nitrogen dioxide
N2O	dinitrogen monoxide or dinitrogen oxide
N2O3	dinitrogen trioxide
N2O5	dinitrogen pentoxide
SO2	sulphur dioxide
SO3	sulphur trioxide
CC14	carbon tetrachloride
CO	carbon monoxide
CO2	carbon dioxide
NaC1	sodium chloride
NaBr	sodium bromide
NaI	sodium iodide
LiCl	lithium chloride
Na2O	sodium oxide
Li2O	lithium oxide
MgCl2	magnesium chloride
FeCl2	ferrous chloride
FeCl3	ferric chloride
FeO	iron(II) oxide or ferrous oxide
Fe2O3	iron(III) oxide or ferric oxide
CuO	copper(II) oxide
Cu2O	copper(I) oxide
ZnCl2	zinc chloride

Video:

State the charges of the following ions with their chemical formula:

 

a. Ammonium: ______

 

b. Silver: ______

 

c. Calcium: ______

 

d. Magnesium: _______

 

e. Carbonate: ________

 

3. Name the following compounds.

a. CaO: ____________________________

 

b. KCl: _____________________________

 

c. Na2SO4: _______________________________________

 

d. Fe2O3: _________________________________________

 

e. CuO: ____________________________

 

f. CO2: __________________________________________