Nomenclature
Binary compounds: A compound containing 2 elements.
1.
Binary compounds: Metal plus Non-metal
The name of the first element (most metallic) is unchanged.
The ending of the second element is changed to “ide”
e.g. NaCl is sodium chloride
To determine the chemical formula of a compound the number of atoms of each element is
found using oxidation numbers.
e.g.
Potassium has an oxidation number of 1+ and sulphur has an oxidation number of 2-,
(Group IA and VIA of the periodic table).
K1+
S2→
K 2S
Name and give the formula for the following compounds.
1.
KCl
1.
strontium sulphide
2.
MgI2
2. barium fluoride
3.
BeO
3. sodium nitride
4.
Ca3N2
4. lithium hydride
2.
Binary Compounds: Non-metal plus Non-metal
 When naming two non-metals a prefix is used to indicate the number of atoms in each
molecule.
 The atom closest to the bottom left corner of the periodic table is named first.
 The atom closest to the top right is named second.
Prefixes
1
2
3
4
5
mono
di
tri
tetra
penta
e.g.
As2S3 is diarsenic trisulphide
6
7
8
9
10
hexa
hepta
octa
nona
deca
prefix + element name and prefix + element with “ide” ending .
Try these:
N2O5
CCl4
AlCl3
phosphorus trihydride
disulphur dichloride
boron trifluoride
3.
Binary Compounds: Transition metal plus non-metal
 Transition metals often have more than one oxidation. state. For example, copper can have an
oxidation state of either 2+ or 1+.
 Therefore copper and oxygen can combine in two ways,
CuO or Cu2O.
 CuO is copper (II) oxide and Cu2O is copper (I) oxide.
 The number in brackets is the oxidation number for copper.
e.g.
nickel (II) chloride is Ni2+ and Cl1- → NiCl2
 Naming the compound when given the formula is sometimes more difficult. For example, name
SnO2.
Tin has an oxidation number of 4+ or 2+. Try both options to determine which type of tin is
combined with oxygen.
Sn2+
O2-
OR
SnO
Sn4+
SnO2
O2→ match
So, the compound is tin (IV) oxide.
Try these:
a)
b)
c)
d)
e)
cobalt (II) nitride
lead (II) oxide
tin (IV) fluoride
copper (I) nitride
cobalt (III) chloride
a) FeCl2
b) FeCl3
c) HgS
d) MnO2
e) PbS2
4. Diatomic Molecules
 atoms that occur naturally in pairs.
 There are seven diatomic molecules.
hydrogen
oxygen
nitrogen
fluorine
H2
O2
N2
F2
chlorine
bromine
iodine
Cl2
Br2
I2