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Brown's Chemistry
Advanced Level Inorganic Chemistry Periodic Table
Revision Notes
Part
6.3 Period 4 trends in bonding,
formulae and oxidation state
A survey of all the
elements of period 4 in terms of metallic/non–metallic character,
electron configuration, atomic radii, ionic radii, oxidation states,
nature and formulae of oxides, nature and formulae of chlorides, nature
and formulae of hydrides. There is also an extra section tabulating a
series of isoelectronic species.
For non–A level
students
KS4 Science GCSE/IGCSE
Periodic Table notes links
INORGANIC
Part 6 Period 4 survey & group trends page
sub–index: 6.1
Survey of
Period 4 elements * 6.2 Period 4 element trends in physical properties * 6.3
Period 4 element trends in bonding,
formulae and oxidation state *
6.4
Important element trends down a Group
Advanced
Level Inorganic Chemistry Periodic Table Index *
Part 1
Periodic Table History
* Part 2
Electron configurations, spectroscopy,
hydrogen spectrum,
ionisation energies *
Part 3
Period 1 survey H to He *
Part 4
Period 2 survey Li to Ne * Part
5 Period 3 survey Na to Ar *
Part 6
Period 4 survey K to Kr and important trends
down a group *
Part 7
s–block Groups 1/2 Alkali Metals/Alkaline Earth Metals *
Part 8
p–block Groups 3/13 to 0/18 *
Part 9
Group 7/17 The Halogens *
Part 10
3d block elements & Transition Metal Series
*
Part 11
Group & Series data & periodicity plots
6.3 Period 4 trends in bonding and
formulae
Krypton is omitted since there is no
relevant or comparable chemistry and the table is more likely to fit on
the page!
Abbreviations: ampho = amphoteric,
cov = covalent
old/latest Group |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
3/13 |
4/14 |
5/15 |
6/16 |
7/17 |
ZSymbol |
19K |
20Ca |
21Sc |
22Ti |
23V |
24Cr |
25Mn |
26Fe |
27Co |
28Ni |
29Cu |
30Zn |
31Ga |
32Ge |
33As |
34Se |
35Br |
element |
potassium |
calcium |
scandium |
titanium |
vanadium |
chromium |
manganese |
iron |
cobalt |
nickel |
copper |
zinc |
gallium |
germanium |
arsenic |
selenium |
bromine |
electron configuration |
[Ar]4s1 |
[Ar]4s2 |
[Ar]3d14s2 |
[Ar]3d24s2 |
[Ar]3d34s2 |
[Ar]3d54s1 |
[Ar]3d54s2 |
[Ar]3d64s2 |
[Ar]3d74s2 |
[Ar]3d84s2 |
[Ar]3d104s1 |
[Ar]3d104s2 |
[Ar]3d14s24p1 |
[Ar]3d14s24p2 |
[Ar]3d14s24p3 |
[Ar]3d14s24p4 |
[Ar]3d14s24p5 |
ox. states |
+1 |
+2 |
+3 |
+2, +3, +4 |
+2,
+3, +4, +5 |
+2, +3, +6 |
+2, +4, +6, +7 |
+2, +3 |
+2, +3 |
+2, +3 |
+1, +2 |
+2 |
+1,
+3 |
+2,
+4 |
+3, +5 |
–2, +2, +4, +6 |
–1, +1, +3, +5, +7 |
oxides |
K2O, K2O2,
KO2 |
CaO |
Sc2O3 |
TiO, TiO2 |
VO, V2O3, VO2, V2O5 |
CrO, Cr2O3, CrO3 |
MnO, MnO2, Mn2O7 |
Fe2O3 |
CoO |
NiO |
Cu2O, CuO |
ZnO |
Ga2O3 |
GeO, GeO2 |
As4O6,
As4O10 |
SeO2, SeO3 |
Br2O, BrO2, BrO3 |
nature of oxides |
basic |
basic |
basic |
basic, ampho |
basic, ampho, ampho, weakly acidic |
basic, ampho, acidic |
basic, ampho, acidic |
ampho? |
basic |
ampho |
basic, basic |
ampho |
ampho |
ampho, weakly acidic |
weakly acidic? |
both weakly acidic |
all acidic |
chlorides |
KCl |
CaCl2 |
ScCl3 |
TiCl3, TiCl4 |
VCl3 |
CrCl3 |
MnCl2 |
FeCl2, FeCl3 |
CoCl2 |
NiCl2 |
CuCl, CuCl2 |
ZnCl2 |
GaCl3 |
GeCl2, GeCl4 |
AsCl3 |
Se2Cl2, SeCl4 |
BrCl |
nature of chlorides |
ionic |
ionic |
ionic |
ionic, covalent |
ionic? |
ionic? |
ionic |
ionic, covalent |
ionic |
ionic |
ionic |
ionic |
? |
ionic, covalent |
covalent |
both cov |
cov |
hydride |
KH |
CaH2 |
? |
? |
? |
? |
? |
? |
? |
? |
? |
? |
GaH3 |
GeH4 |
AsH3 |
H2Se |
HBr |
nature of hydride |
ionic |
ionic |
? |
? |
? |
? |
? |
? |
? |
? |
? |
? |
cov |
covalent |
covalent |
cov |
cov |
-
The patterns across
Period 4 are not as clear cut as for periods 2 and 3 – one reason
being the interjection of the 3d block of metals
-
Metallic or
non–metallic character:
-
From far left
(metallic) to the far right (non–metallic) the non–metallic
character increases as the electronegativity and ionisation
energies increase.
-
This trend shows up as
the electronegativity difference in M–X decreases (M to the left
of X)
-
(i) the ionic bonding of
the giant ionic lattice ==> covalent
bonding character of small molecules of the oxides and chlorides
-
(ii) the oxide
changes from basic ==> amphoteric ==> acidic
-
BUT within the 3d block
the patterns are quite complicated and the oxidation state of the
metal very much determines the structural and chemical character of
the compound.
-
Oxidation states
-
From potassium (+1) to
manganese (+7) the maximum oxidation state is determined by the
maximum number of outer valency electrons.
-
After Mn, there is a
tendency to fall to a stable +2 state e.g. cobalt, nickel,
copper and zinc.
-
Beyond zinc, the last
element in the 3d block, the maximum oxidation state is governed
by the maximum number of s + p electrons beyond the full 3d
sub–shell i.e. from gallium to bromine the maximum oxidation
state rises from +3 to +7.
-
Oxides – formulae,
bonding and chemical character
-
Ionic lattice ==>
covalent character of the oxides and chlorides
-
and in chemical character the oxide changes
from basic ==> amphoteric ==> acidic.
-
The oxide of maximum
oxidation state for potassium to manganese is determined by the maximum
number of outer valency electrons (from 1 to 5).
-
Again the patterns within
the 3d block are complicated.
-
Chlorides – formulae,
bonding and chemical character
-
Radii of isoelectronic
ions
-
Isoelectronic means species having the same total
number of electrons.
-
The table below considers
the isoelectronic ions associated with Periods 2, 3 and 4.
-
isoelectronic system |
Group 4/14 |
Group 5/15 |
Group 6/16 |
Group 7/17 |
(Group 0/18) |
Group 1 |
Group 2 |
Group 3/13 |
Period |
Period 2 |
Period 3 |
[Ne]
10e 1s22s22p6 |
C4– |
N3– |
O2– |
F– |
(Ne) |
Na+ |
Mg2+ |
Al3+ |
total nuclear charge |
+6 |
+7 |
+8 |
+9 |
(+10) |
+11 |
+12 |
+13 |
radius
in
picometre (pm) |
260 |
171 |
140 |
136 |
(38–112*) |
95 |
65 |
50 |
name of ion |
carbide |
nitride |
oxide |
fluoride |
(neon) |
sodium |
magnesium |
aluminium |
Period |
Period 3 |
Period 4 |
[Ar]
18e 1s22s22p63s23p6 |
Si4– |
P3– |
S2– |
Cl– |
(Ar) |
K+ |
Ca2+ |
Sc3+ |
nuclear charge |
+14 |
+15 |
+16 |
+17 |
(+18) |
+19 |
+20 |
+21 |
radius
in
picometre (pm) |
271 |
212 |
184 |
181 |
(71–154*) |
133 |
99 |
81 |
name of ion |
silicide |
phosphide |
sulfide |
chloride |
(argon) |
potassium |
calcium |
scandium |
-
Excluding the noble gases
themselves, there is a clear pattern of decreasing ionic radius with
increase in nuclear charge (+ atomic/proton number) for the two
isoelectronic series tabulated above.
-
From left to right the
proton/electron ratio is steadily increasing so that the electrons are
experiencing an increasingly greater attractive force of the nucleus,
hence the steady decrease in radii for an isoelectronic series.
-
* all sorts of values
are quoted for noble gas radii e.g. atomic, covalent and ionic, but most
don't fit in the pattern above which is quite clear for all the cations and
anions listed.
WHAT NEXT?
See also
4.1 Period 2 Survey of the
individual elements, 4.2 Period
2 element trends and explanations of physical properties * 4.3 Period 2 element trends in bonding,
structure, oxidation state, formulae & reactions,
5.1
Period 3 survey of elements,
5.2 Period 3 element trends
& explanations of physical properties, 5.3
Period 3 element trends in bonding, structure, oxidation
state, formulae & reactions, 6.2 Period 4
element trends in physical properties,
6.4
Important element trends down a Group
INORGANIC
Part 6 Period 4 survey & group trends page
sub–index: 6.1
Survey of
Period 4 elements * 6.2 Period 4 element trends in physical properties * 6.3
Period 4 element trends in bonding,
formulae and oxidation state *
6.4
Important element trends down a Group
Advanced
Level Inorganic Chemistry Periodic Table Index *
Part 1
Periodic Table history
* Part 2
Electron configurations, spectroscopy,
hydrogen spectrum,
ionisation energies *
Part 3
Period 1 survey H to He *
Part 4
Period 2 survey Li to Ne * Part
5 Period 3 survey Na to Ar *
Part 6
Period 4 survey K to Kr and important trends
down a group *
Part 7
s–block Groups 1/2 Alkali Metals/Alkaline Earth Metals *
Part 8
p–block Groups 3/13 to 0/18 *
Part 9
Group 7/17 The Halogens *
Part 10
3d block elements & Transition Metal Series
*
Part 11
Group & Series data & periodicity plots
TOP OF PAGE
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