Periodic system

the periodic system of the elements (short periodic system or PSE) offers an overview of the different chemical elements. The elements are divided with rising nuclear charge (ordinal number) according to their chemical characteristics in periods as well as main and Nebengruppen.

Periodic system thatElements

table of contents

representation

is represented in the following the periodic system in his today most well-known form. The elements are specified with their ordinal number and their symbol. (over the ordinal number 118 extended periodic system is under extended periodic system). Apart from the variant - also as long periodic system, represented down , designation, there is still another alternative assortment, which is called short periodic system.


Group 1
IN GENERAL
2
II A
3
III B
4
IV B
5
V B
6
VI B
7
VII B
8
VIII B
9
VIII B
10
VIII B
11
I B
12
II B
13
III A
14
IV A
15
V A
16
VI A
17
VII A
18
VIII A
period bowl
1 1
H
2
He
K
2 3
left
4
5
B
6
C
7
N
8
O
9
F
10
Ne
L
3 11
well
12
mg
13
aluminium
14
SI
15
P
16
S
17
Cl
18
acre
M
4 19
K
20
approx.
21
sports club
22
Ti
23
V
24
CR
25
Mn
26
Fe
27
CO
28
never
29
cu
30
Zn
31
Ga
32
Ge
33
As
34
SE
35
Br
36
Kr
N
5 37
Rb
38
SR
39
Y
40
Zr
41
Nb
42
Mo
43
Tc
44
Ru
45
RH
46
Pd
47
AG
48
CD
49
in
50
SN
51
self-service
52
width unit
53
I
54
Xe
O
6 55
Cs
56
Ba
* 72
Hf
73
TA
74
W
75
RH
76
OS
77
IR
78
Pt
79
outer ones
80
Hg
81
tl
82
Pb
83
Bi
84
Po
85
RKs
86
Rn
P
7 87
Fr
88
RA
** 104
Rf
105
railways
106
Sg
107
Bh
108
Hs
109
Mt
110
DS
111
Rg
112
Uub
113
Uut
114
Uuq
115
Uup
116
Uuh
117
Uus
118
Uuo
Q
* Lanthanoide 57
La
58
Ce
59
Pr
60
lp
61
Pm
62
Sm
63
European Union
64
Gd
65
Tb
66
Dy
67
Ho
68
it
69
TM
70
Yb
71
Lu
** Actinoide 89
AC
90
Th
91
Pa
92
U
93
NP
94
Pu
95
to
96
cm
97
UC
98
Cf
99
it
100
FM
101
MD
102
NO
103
Lr



Putting one: Natural elements of alkali metals of alkaline earth metals Lanthanoide Actinoide of transition metals
Artificial elements of metals of metalloids of halogens of noble gases of nonmetals

history

Briefmarkenblock zur Ehrung Mendelejews
stamp block for the honour of Mendeleyev

the dating of the discovery of such elements, which already admits since the early period or antique one is, is only inaccurate and can depending upon source of literature overseveral centuries vary. Safer datings are only starting from that 18. Century possible. Up to then only 15 elements were well-known as such and described (metals such as iron, copper, lead, bismuth, arsenic, zinc, tin, Antimony, platinum, silver, mercury and gold or nonmetals such as carbon, sulfur and phosphorus).

Most elements became in 19. Century discovered and scientifically described. At the beginning 20. Century were only ten of the naturalElements unknown. Since that time above all with difficulty accessible, often radioactive elements were represented. Many of these elements occur not in nature and are the product of artificial nuclear fusion processes. Only in December 1994 the two artificial elements Darmstadtium became (Eka platinum) and Roentgenium (Eka gold) manufactured.

Beginning 19. Century determined Johann Wolfgang Döbereiner for the first time a connection between the atomic mass and the chemical characteristics of individual elements. 1863 placed new country a table of the elements arranged according to atomic masses in groups of eight (law thatOktaven) up. The periodic system was set up to 1869 almost at the same time and independently by Dimitri Mendeleyev (1834-1907) and Lothar Meyer (1830-1895). They arranged likewise the chemical elements according to rising atomic masses, whereby them elements with similar characteristics (amount of that Bonding electrons) arranged among themselves. In 20. Century was discovered the structure of the atoms, which became periodicity by the structure of the electron sheath avowedly.

See also: Development of the periodic system of the elements

structure

the chemical characteristics of an element become onlyby the characteristics of the electron sheath certainly, the characteristics of the atomic nucleus do not play a role up to the nuclear charge, which specifies the number of orbital electrons. The periodic system is explainable thereby completely by the Elektronenkonfiguration of the atoms.

The elements in one period (linethe PSE), the elements of a group (column of the PSE) have the same number of electron shells resemble themselves in the structure of the outside electron shell. The classical distinction in main and Nebengruppen arises as a result of the fact that with the latters not the extreme, butthe secondaryextreme bowl with electrons is filled up, with the Lanthanoiden and Actinoiden the third-extreme.

Exceptions of these rules are rare, but possible, as for example with the elements copper or chrome.

The number of electrons on that essentially determines, therefore the elements of the individual groups, since they have the same number of electrons on the outside course, have outside electron shell the chemical behavior of an atom comparable chemical characteristics.

The element 83 (bismuth [Bi]) and all following are radioactive and thus unstably. Also within the elements 1 to 82 2 materials are contained, which are radioactive, thus unstable: 43 (technetium [Tc]) and 61 (promethium [Pm]). Thus actually only 80 stable elements remain, in thatSeem to nature - all different are radioactive substances. From the radioactive elements only thorium and uranium are in larger quantities in nature present, since these elements have radioactive half-lives in the order of magnitude of the age of the earth. All other radioactive elementssind entweder intermediäre Zerfallsprodukte desUrans und Thoriums, wie das Radium oder entstehen bei seltenen natürlichen Kernreaktionen oder durch Spontanspaltung von Uran und Thorium. The latters can be only artificially manufactured in balancable quantities. This applies in principle to allElements with ordinal numbers over 94, from which to today still no traces in nature were found, although they likewise develop with the element synthesis in supernew facts.

one

can state tendencies in the periodic system that some characteristics thatElements in certain positions in the periodic system to find leave themselves. Thus it appears logically that the number of protons increases from left to right in a line and from top to bottom in a column. Thus there are further characteristics, thosein the periodic system to represent leave themselves:

see also

Web on the left of

Commons: Periodic system - pictures, videos and/or audio files
Wiktionary: To periodic system - word origin, synonyms and translations
 

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