Name __________________
Naming Molecular Compounds
Period ______
Chem Worksheet 9-2
A molecular compound is a group of atoms held together by a covalent bond. Compounds made
entirely of non-metals are generally molecular compounds. Carbon tetrachloride, CCl4, is an example of a
molecular compound. When naming these compounds prefixes are used to denote how many of each atom
is bonded in the compound. However, the prefix mono- is not used with the first element in the compound,
even if there is only one element. The ending of the second element in the compound is always changed to
–ide, in the same way the ending is changed for monatomic anions.
Rules for naming Molecular Compounds
1. Name the first element using the element’s full name.
2. Name the second element using the –ide ending.
3. Use prefixes to tell how many of each element is present.
(do not use the prefix mono- on the first element).
Naming Prefixes
1
mono2
di3
tri4
tetra5
penta6
hexa7
hepta8
octa9
nona10
deca-
Examples
#1. Write the chemical formula for diphosphorus pentoxide
- this compound contains two phosphorus atoms and five oxygen atoms:
P2O5
#2. Name the following compound: IF7.
- there is one iodine and there are seven fluorine atoms:
heptafluoride
iodine
(the prefix mono- is not used on the first element and that the ending of fluorine is changed to –ide.)
Fill in the following table with the missing information.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Formula
SO2
503
N2 O4
102
P4O10
CSz
NO2
N2Cl4
XeFa
S Cl
2
ICI
2
P2 S5
Name
SulfurDioxide
Sulfur trioxide
Dinitrogen Tetroxide
Chlorine dioxide
Tetraphosphorous Decoxide
Carbon disulfide
Nitrogen Dioxide
Dinitrogen Tetrachloride
Xenon difluoride
DisulfurDichloride
Iodine trichloride
Diphosphorous Pentasulfide
© John Erickson, 2005
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
X
Formula
SF6
R 56
SeO2
NHz
Bcb
N2 O
BrF5
CO2
CO
ClF3
ICI
CH4
Name
Sulfur Hexafluoride
Tetraphosphorus hexasulfide
Selenium Dioxide
X
Ammonia
Trihydride
Nitrogen
Boron trichloride
Dinitrogen Monoxide
Bromine pentafluoride
Carbon dioxide
Carbon monoxide
chlorinetrifluoride
Iodine monochloride
Carbontetra
hydride
WS9-2NamingMolec.docx