Chemistry Reference
In-Depth Information
•
The elements in the group III B: scandium, yttrium, lanthanum and actin-
ium that have an incompletely filled d subshell in their atomic state: (n − 1)d
1
ns
2
. Although both lanthanum and actinium could be included in the d tran-
sition metal series, they are very similar physically and chemically to the
elements in the f-block and therefore are considered to be f-type transition
elements (4f-, 5f-type transition elements, respectively). The last element of
the lanthanides series, lutetium, also has a partly filled d orbital (
Table 2.6
)
and could also be included in the d transition metal group. However, it
has similar properties to the 4f-type transition metals, where it is usually
grouped with lanthanum and the rest of the lanthanides series.
Zinc, cadmium, and mercury are considered d-block elements, but are not
included in the transition metals category because their d-shell is full in the atomic
state (the electronic configuration is d
10
s
2
) and they only have the oxidation state two
with the electronic configuration of their ions: d
10
s
0
. Because they have a similar
chemical behavior to the transition metals, they are studied along with the elements
in the d-block.
The d-block elements can have variable chemical reactivities compared to the
other metallic elements, either representative elements or f-type transition metals.
They can have several oxidation states (Tables 2.7 and 2.8), and have a higher ten-
dency to form metal complexes. Metal cations can form coordination complexes
with different types of electron-donating groups, and these complexes are the active
species in biological environments (Krantzberg 1989; Lepădatu et al. 2009).
The f-block elements are the lanthanides and the actinides. Each of these series
consists of 14 elements with similar properties in both atomic state and in their com-
bination. They are situated in the 6
th
and 7
th
period of the periodic table, respectively,
but are customarily separated from the main body of the table. These elements fill
their 4f and their 5f orbital, respectively (Table 2.6). The lanthanides are more reac-
tive than the d-block metals, behaving more like the alkali earth metals. Actinides
are all very radioactive and therefore have high lethality. The actinides, with atomic
numbers higher than 92, have been synthesized during nuclear reactions.
TABLE 2.7
Characteristic Oxidation States of s, p, d and f Metals
s-Type Metals
p-Type Metals
d-Type Metals
f-Type Metals
Have just one oxidation
state
Group 1: +1
Group 2: +2
Have two oxidation
states, 2 units
difference between
them
Group 13: +1; +3
Group 14: +2; +4
Group 15: +3; +5
The +2 oxidation state
is present; there are
also several higher
oxidation states, one
unit difference
between them
The lanthanides: +3
almost exclusively
The actinides: +3,
however the first 5
elements can have
several higher
oxidation states
