Chemistry Reference
In-Depth Information
Table 6.2
Classical Names of Some Common Cations
Periodic
Ion of Lower
Ion of Higher
Group
Charge
Charge
Cr
2
,
Cr
3
,
VIB
chromous
chromic
Mn
2
,
Mn
3
,
VIIB
manganous
manganic
Fe
2
,
Fe
3
,
VIII
ferrous
ferric
Co
2
,
Co
3
,
VIII
cobaltous
cobaltic
Ni
2
,
Ni
3
,
VIII
nickelous
nickelic
Cu
,
Cu
2
,
IB
cuprous
cupric
Au
,
Au
3
,
IB
aurous
auric
Hg
2
2
,
Hg
2
,
IIB
mercurous
mercuric
Sn
2
,
Sn
4
,
IVA
stannous
stannic
Pb
2
,
Pb
4
,
IVA
plumbous
plumbic
An older nomenclature system (known as the classical system) uses suf-
fixes to distinguish metal ions of the variable type. As Figure 5.11 shows, there
are two possible monatomic cations for each variable metal listed. The ion with
the higher charge is named with the ending changed to -
ic
. The ion of lower
charge has its ending changed to -
ous
. For example, is called chromous
ion, and is called chromic ion. For many elements, the Latin names are
used instead of the English names. For example, is called ferrous ion—
from
ferrum,
the Latin for iron. Table 6.2 lists classical names for some impor-
tant monatomic cations. This older system is more difficult to use in two ways:
(1) we must remember the other possible charge on an ion in addition to the
one given, and (2) we must remember a Latin name for many of the elements.
Cr
2
Cr
3
Fe
2
EXAMPLE 6.10
V
2
Name using the Stock system. Explain why use of the classical system
would be harder.
Solution
The Stock system name—vanadium(II) ion—is easy. To use the classical sys-
tem, we must know the answers to at least three questions: (1) What is the
charge on the other monatomic ion of vanadium? (2) Is the Latin name for vana-
dium used in the classical system? (3) If the Latin name is used, what is that
name? The Stock system was invented to make naming easier.
Ti
3
.
Practice Problem 6.10
Name
Naming Anions
Just as for cations, there are three types of anions for naming purposes. Monatomic
anions are easy to name. A second type,
oxoanions,
are anions that contain oxy-
gen covalently bonded to another element. Table 6.3 presents some important
