Periodic table (standard)

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This is a typical display of the periodic table of the elements and contains the symbol and atomic number of each element. The periodic table of the chemical elements is a tabular method of displaying the chemical elements. Although precursors to this table exist, its invention is generally credited to Russian chemist Dmitri Mendeleev in 1869. Mendeleev intended the table to illustrate recurring ("periodic") trends in the properties of the elements. The layout of the table has been refined and extended over time, as new elements have been discovered, and new theoretical models have been developed to explain chemical behavior.^[1]

The periodic table is now ubiquitous within the academic discipline of chemistry, providing an extremely useful framework to classify, systematize and compare all the many different forms of chemical behavior. The table has also found wide application in physics, biology, engineering, and industry. The current standard table contains 117 confirmed elements as of 2008-01-27 (while element 118 has been synthesized, element 117 has not).

[edit] Table

Group # 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Period

1 1
H
2
He

2 3
Li 4
Be
5
B 6
C 7
N 8
O 9
F 10
Ne

3 11
Na 12
Mg
13
Al 14
Si 15
P 16
S 17
Cl 18
Ar

4 19
K 20
Ca 21
Sc 22
Ti 23
V 24
Cr 25
Mn 26
Fe 27
Co 28
Ni 29
Cu 30
Zn 31
Ga 32
Ge 33
As 34
Se 35
Br 36
Kr

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
Sb 52
Te 53
I 54
Xe

6 55
Cs 56
Ba *
72
Hf 73
Ta 74
W 75
Re 76
Os 77
Ir 78
Pt 79
Au 80
Hg 81
Tl 82
Pb 83
Bi 84
Po 85
At 86
Rn

7 87
Fr 88
Ra **
104
Rf 105
Db 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

* Lanthanides 57
La 58
Ce 59
Pr 60
Nd 61
Pm 62
Sm 63
Eu 64
Gd 65
Tb 66
Dy 67
Ho 68
Er 69
Tm 70
Yb 71
Lu

** Actinides 89
Ac 90
Th 91
Pa 92
U 93
Np 94
Pu 95
Am 96
Cm 97
Bk 98
Cf 99
Es 100
Fm 101
Md 102
No 103
Lr

This common arrangement of the periodic table separates the lanthanides and actinides from other elements. The wide periodic table incorporates the f-block. The extended periodic table adds the 8th and 9th periods, incorporating the f-block and adding the theoretical g-block.

Element categories in the periodic table

Metals Metalloids Nonmetals Unknown

Alkali metals Alkaline earth metals Inner transition elements Transition elements Other metals Other nonmetals Halogens Noble gases

Lanthanides Actinides

Atomic number colors show state at standard temperature and pressure (0 Â°C and 1 atm)

Solids Liquids Gases Unknown

Borders show natural occurrence

Primordial From decay Synthetic Undiscovered