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Encyclopedia > Periodic table

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] Primo Michele Levi (July 31, 1919 – April 11, 1987) was a Jewish Italian chemist, Holocaust survivor and author of memoirs, short stories, poems, and novels. ... The elements that are titles of the stories. ... A table is a mode of visual communication that maps the logical structure of a set of data into a hierarchical matrix. ... The periodic table of the chemical elements A chemical element, or element, is a type of atom that is defined by its atomic number; that is, by the number of protons in its nucleus. ... A chemist pours from a round-bottom flask. ... Portrait of Dmitri Mendeleev by Ilya Repin (Russian: , Dmitri Ivanovich Mendeleev  ) (8 February [O.S. 27 January] 1834 in Tobolsk – 2 February [O.S. 20 January] 1907 in Saint Petersburg), was a Russian chemist and inventor. ...


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 October 16, 2006 (while element 118 has been synthesized, element 117 has not). For other uses, see Chemistry (disambiguation). ... A chemical substance is any material substance used in or obtained by a process in chemistry: A chemical compound is a substance consisting of two or more chemical elements that are chemically combined in fixed proportions. ... A magnet levitating above a high-temperature superconductor demonstrates the Meissner effect. ... For the song by Girls Aloud see Biology (song) Biology studies the variety of life (clockwise from top-left) E. coli, tree fern, gazelle, Goliath beetle Biology (from Greek: βίος, bio, life; and λόγος, logos, speech lit. ... Engineering is the discipline of acquiring and applying knowledge of design, analysis, and/or construction of works for practical purposes. ... is the 289th day of the year (290th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... General Name, Symbol, Number ununoctium, Uuo, 118 Chemical series noble gases Group, Period, Block 18, 7, p Appearance unknown, probably colorless Atomic mass predicted, (314) g/mol Electron configuration perhaps [Rn] 5f14 6d10 7s2 7p6 (guess based on radon) Electrons per shell 2, 8, 18, 32, 32, 18, 8 Phase... General Name, Symbol, Number ununseptium, Uus, 117 Chemical series presumably halogens Group, Period, Block 17, 7, p Appearance unknown, probably dark metallic Standard atomic weight predicted, (310) g·mol−1 Electron configuration perhaps [Rn] 5f14 6d10 7s2 7p5 (guess based on astatine) Electrons per shell 2, 8, 18, 32, 32...

Contents

Methods for displaying the periodic table

Standard periodic 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 f-block from other elements. The Wide Periodic Table incorporates the f-block; the Extended Periodic Table incorporates the f-block and adds the theoretical g-block. A periodic table group is a vertical column in the periodic table of the chemical elements. ... The alkali metals are a series of elements comprising Group 1 (IUPAC style) of the periodic table: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). ... The alkaline earth metals are a series of elements comprising Group 2 (IUPAC style) of the periodic table: beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba) and radium (Ra). ... A Group 3 element is an element in periodic table group 3 (IUPAC style) in the periodic table, which consists of: scandium (21) yttrium (39) lanthanum (57) - lutetium (71) actinium (89) - lawrencium (103) All of these elements are classed in Group 3 because their outer shell holds three electrons. ... A Group 4 element is an element in periodic table group 4 (IUPAC style) in the periodic table, which consists of: titanium (22) zirconium (40) hafnium (72) rutherfordium (104) All of these elements are classed in Group 4 because their valence shell holds four electrons. ... A Group 5 element is the series of elements in group 5 (IUPAC style) in the periodic table, which consists of vanadium (V), niobium (Nb), tantalum (Ta), and dubnium (Db). ... The group 6 in the periodic table consists of the elements chromium (24) molybdenum (42) tungsten (74) seaborgium (106) Group 6 is the new IUPAC name for this group, the old style name was group VIA in the old European system or group VIB in the old US system. ... A Group 7 element is an element in periodic table group 7 (IUPAC style) in the periodic table, which consists of: manganese (25) technetium (43) rhenium (75) bohrium (107) All of these elements are classed in Group 7 because their valence shell holds four electrons. ... A Group 8 element is an element in periodic table group 8 (IUPAC style) in the periodic table, which consists of: Iron (26) Ruthenium (44) Osmium (76) Hassium (108) All of these elements are classed in Group 8 because their valence shell holds four electrons. ... The Group 9 elements are: Cobalt (27) Rhodium (45) Iridium (77) Meitnerium (109) Color coding for these atomic numbers: At room temperature, all are solid; red indicates item is synthetic and does not occur naturally. ... The Group 10 elements are: Nickel (28) Palladium (46) Platinum (78) Darmstadtium (110) Color coding for these atomic numbers: At room temperature, all are solid; red indicates item is synthetic and does not occur naturally. ... A Group 11 element is one in the series of elements in group 11 (IUPAC style) in the periodic table, consisting of transition metals which are the traditional coinage metals of copper (Cu), silver (Ag), and gold (Au). ... The Group 12 elements are: Zinc (30) Cadmium (48) Mercury (80) Ununbium (112) Color coding for these atomic numbers: At room temperature, all are solid but mercury is liquid; red indicates item is synthetic and does not occur naturally. ... The Boron group is the series of elements in group 13 (IUPAC style) in the periodic table. ... The carbon group is group 14 (IUPAC style) in the periodic table. ... Nitrogen is the 7th element in the Periodic Table. ... The chalcogens (with the ch pronounced with a hard c as in chemistry) are the name for the periodic table group 16 (old-style: VIB or VIA) in the periodic table. ... This article is about the chemical series. ... This article is about the chemical series. ... In the periodic table of the elements, a period is a row of the table. ... A period 1 element is one of the chemical elements in the first row (or period) of the periodic table of the elements. ... This article is about the chemistry of hydrogen. ... For other uses, see Helium (disambiguation). ... A period 2 element is one of the chemical elements in the second row (or period) of the periodic table of the elements. ... This article is about the chemical element named Lithium. ... General Name, symbol, number beryllium, Be, 4 Chemical series alkaline earth metals Group, period, block 2, 2, s Appearance white-gray metallic Standard atomic weight 9. ... General Name, Symbol, Number boron, B, 5 Chemical series metalloids Group, Period, Block 13, 2, p Appearance black/brown Standard atomic weight 10. ... For other uses, see Carbon (disambiguation). ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ... Distinguished from fluorene and fluorone. ... For other uses, see Neon (disambiguation). ... A period 3 element is one of the chemical elements in the third row (or period) of the periodic table of the elements. ... For sodium in the diet, see Edible salt. ... General Name, symbol, number magnesium, Mg, 12 Chemical series alkaline earth metals Group, period, block 2, 3, s Appearance silvery white solid at room temp Standard atomic weight 24. ... Aluminum redirects here. ... Not to be confused with Silicone. ... General Name, symbol, number phosphorus, P, 15 Chemical series nonmetals Group, period, block 15, 3, p Appearance waxy white/ red/ black/ colorless Standard atomic weight 30. ... This article is about the chemical element. ... General Name, symbol, number chlorine, Cl, 17 Chemical series halogens Group, period, block 17, 3, p Appearance yellowish green Standard atomic weight 35. ... General Name, symbol, number argon, Ar, 18 Chemical series noble gases Group, period, block 18, 3, p Appearance colorless Standard atomic weight 39. ... A period 4 element is one of the chemical elements in the fourth row (or period) of the periodic table of the elements. ... General Name, symbol, number potassium, K, 19 Chemical series alkali metals Group, period, block 1, 4, s Appearance silvery white Standard atomic weight 39. ... For other uses, see Calcium (disambiguation). ... General Name, Symbol, Number scandium, Sc, 21 Chemical series transition metals Group, Period, Block 3, 4, d Appearance silvery white Atomic mass 44. ... General Name, symbol, number titanium, Ti, 22 Chemical series transition metals Group, period, block 4, 4, d Appearance silvery metallic Standard atomic weight 47. ... General Name, symbol, number vanadium, V, 23 Chemical series transition metals Group, period, block 5, 4, d Appearance silver-grey metal Standard atomic weight 50. ... REDIRECT [[ Insert text]]EWWWWWWWWWWWWW YO General Name, symbol, number chromium, Cr, 24 Chemical series transition metals Group, period, block 6, 4, d Appearance silvery metallic Standard atomic weight 51. ... General Name, symbol, number manganese, Mn, 25 Chemical series transition metals Group, period, block 7, 4, d Appearance silvery metallic Standard atomic weight 54. ... For other uses, see Iron (disambiguation). ... For other uses, see Cobalt (disambiguation). ... For other uses, see Nickel (disambiguation). ... For other uses, see Copper (disambiguation). ... General Name, symbol, number zinc, Zn, 30 Chemical series transition metals Group, period, block 12, 4, d Appearance bluish pale gray Standard atomic weight 65. ... General Name, Symbol, Number gallium, Ga, 31 Chemical series poor metals Group, Period, Block 13, 4, p Appearance silvery white   Standard atomic weight 69. ... General Name, Symbol, Number germanium, Ge, 32 Chemical series metalloids Group, Period, Block 14, 4, p Appearance grayish white Standard atomic weight 72. ... General Name, Symbol, Number arsenic, As, 33 Chemical series metalloids Group, Period, Block 15, 4, p Appearance metallic gray Standard atomic weight 74. ... For other uses, see Selenium (disambiguation). ... Bromo redirects here. ... For other uses, see Krypton (disambiguation). ... A period 5 element is one of the chemical elements in the fifth row (or period) of the periodic table of the elements. ... General Name, Symbol, Number rubidium, Rb, 37 Chemical series alkali metals Group, Period, Block 1, 5, s Appearance grey white Standard atomic weight 85. ... General Name, Symbol, Number strontium, Sr, 38 Chemical series alkaline earth metals Group, Period, Block 2, 5, s Appearance silvery white metallic Standard atomic weight 87. ... General Name, Symbol, Number yttrium, Y, 39 Chemical series transition metals Group, Period, Block 3, 5, d Appearance silvery white Standard atomic weight 88. ... General Name, Symbol, Number zirconium, Zr, 40 Chemical series transition metals Group, Period, Block 4, 5, d Appearance silvery white Standard atomic weight 91. ... General Name, Symbol, Number niobium, Nb, 41 Chemical series transition metals Group, Period, Block 5, 5, d Appearance gray metallic Standard atomic weight 92. ... General Name, Symbol, Number molybdenum, Mo, 42 Chemical series transition metals Group, Period, Block 6, 5, d Appearance gray metallic Standard atomic weight 95. ... General Name, Symbol, Number technetium, Tc, 43 Chemical series transition metals Group, Period, Block 7, 5, d Appearance silvery gray metal Standard atomic weight [98](0) g·mol−1 Electron configuration [Kr] 4d5 5s2 Electrons per shell 2, 8, 18, 13, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number Ruthenium, Ru, 44 Chemical series transition metals Group, Period, Block 8, 5, d Appearance silvery white metallic Atomic mass 101. ... General Name, Symbol, Number rhodium, Rh, 45 Chemical series transition metals Group, Period, Block 9, 5, d Appearance silvery white metallic Standard atomic weight 102. ... For other uses, see Palladium (disambiguation). ... This article is about the chemical element. ... General Name, Symbol, Number cadmium, Cd, 48 Chemical series transition metals Group, Period, Block 12, 5, d Appearance silvery gray metallic Standard atomic weight 112. ... General Name, Symbol, Number indium, In, 49 Chemical series poor metals Group, Period, Block 13, 5, p Appearance silvery lustrous gray Standard atomic weight 114. ... This article is about the metallic chemical element. ... This article is about the element. ... General Name, Symbol, Number tellurium, Te, 52 Chemical series metalloids Group, Period, Block 16, 5, p Appearance silvery lustrous gray Standard atomic weight 127. ... For other uses, see Iodine (disambiguation). ... General Name, Symbol, Number xenon, Xe, 54 Chemical series noble gases Group, Period, Block 18, 5, p Appearance colorless Standard atomic weight 131. ... A period 6 element is one of the chemical elements in the sixth row (or period) of the periodic table of the elements, including the Lanthanides. ... General Name, Symbol, Number caesium, Cs, 55 Chemical series alkali metals Group, Period, Block 1, 6, s Appearance silvery gold Standard atomic weight 132. ... For other uses, see Barium (disambiguation). ... The lanthanide series is the 14 rare earth chemical elements which lie between lanthanum and ytterbium on the periodic table. ... General Name, Symbol, Number tantalum, Ta, 73 Chemical series transition metals Group, Period, Block 5, 6, d Appearance gray blue Standard atomic weight 180. ... For other uses, see Tungsten (disambiguation). ... General Name, Symbol, Number rhenium, Re, 75 Chemical series transition metals Group, Period, Block 7, 6, d Appearance grayish white Standard atomic weight 186. ... General Name, Symbol, Number osmium, Os, 76 Chemical series transition metals Group, Period, Block 8, 6, d Appearance silvery, blue cast Standard atomic weight 190. ... This article is about the chemical element. ... General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Standard atomic weight 195. ... GOLD refers to one of the following: GOLD (IEEE) is an IEEE program designed to garner more student members at the university level (Graduates of the Last Decade). ... General Name, Symbol, Number mercury, Hg, 80 Chemical series transition metals Group, Period, Block 12, 6, d Appearance silvery Standard atomic weight 200. ... General Name, Symbol, Number thallium, Tl, 81 Chemical series poor metals Group, Period, Block 13, 6, p Appearance silvery white Standard atomic weight 204. ... This article is about the metal. ... General Name, Symbol, Number bismuth, Bi, 83 Chemical series poor metals Group, Period, Block 15, 6, p Appearance lustrous pink Standard atomic weight 208. ... General Name, Symbol, Number polonium, Po, 84 Chemical series metalloids Group, Period, Block 16, 6, p Appearance silvery Standard atomic weight (209) g·mol−1 Electron configuration [Xe] 4f14 5d10 6s2 6p4 Electrons per shell 2, 8, 18, 32, 18, 6 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number astatine, At, 85 Chemical series halogens Group, Period, Block 17, 6, p Appearance metallic (presumed) Standard atomic weight (210) g·mol−1 Electron configuration [Xe] 4f14 5d10 6s2 6p5 Electrons per shell 2, 8, 18, 32, 18, 7 Physical properties Phase solid Melting point 575 K... For other uses, see Radon (disambiguation). ... A period 7 element is one of the chemical elements in the seventh row (or period) of the periodic table of the elements. ... General Name, Symbol, Number francium, Fr, 87 Chemical series alkali metals Group, Period, Block 1, 7, s Appearance metallic Standard atomic weight (223) g·mol−1 Electron configuration [Rn] 7s1 Electrons per shell 2, 8, 18, 32, 18, 8, 1 Physical properties Phase  ? solid Density (near r. ... General Name, Symbol, Number radium, Ra, 88 Chemical series alkaline earth metals Group, Period, Block 2, 7, s Appearance silvery white metallic Standard atomic weight (226) g·mol−1 Electron configuration [Rn] 7s2 Electrons per shell 2, 8, 18, 32, 18, 8, 2 Physical properties Phase solid Density (near r. ... The actinide series encompasses the 14 chemical elements that lie between actinium and nobelium on the periodic table with atomic numbers 89 - 102 inclusive. ... General Name, Symbol, Number dubnium, Db, 105 Chemical series transition metals Group, Period, Block 5, 7, d Appearance unknown, probably silvery white or metallic gray Atomic mass (262) g/mol Electron configuration perhaps [Rn] 5f14 6d3 7s2 (guess based on tantalum) Electrons per shell 2, 8, 18, 32, 32, 11... General Name, Symbol, Number seaborgium, Sg, 106 Chemical series transition metals Group, Period, Block 6, 7, d Appearance unknown, probably silvery white or metallic gray Atomic mass (266) g/mol Electron configuration perhaps [Rn] 5f14 6d4 7s2 (guess based on tungsten) Electrons per shell 2, 8, 18, 32, 32, 12... General Name, Symbol, Number bohrium, Bh, 107 Chemical series transition metals Group, Period, Block 7, 7, d Appearance unknown, probably silvery white or metallic gray Atomic mass (264) g/mol Electron configuration perhaps [Rn] 5f14 6d5 7s2 (guess based on rhenium) Electrons per shell 2, 8, 18, 32, 32, 13... General Name, Symbol, Number hassium, Hs, 108 Chemical series transition metals Group, Period, Block 8, 7, d Appearance unknown, probably silvery white or metallic gray Atomic mass (269) g/mol Electron configuration perhaps [Rn] 5f14 6d6 7s2 (guess based on osmium) Electrons per shell 2, 8, 18, 32, 32, 14... General Name, Symbol, Number meitnerium, Mt, 109 Chemical series transition metals Group, Period, Block 9, 7, d Appearance unknown, probably silvery white or metallic gray Atomic mass (268) g·mol−1 Electron configuration perhaps [Rn] 5f14 6d7 7s2 (guess based on iridium) Electrons per shell 2, 8, 18, 32, 32... General Name, Symbol, Number darmstadtium, Ds, 110 Chemical series transition metals Group, Period, Block 10, 7, d Appearance unknown, probably silvery white or metallic gray Atomic mass (281) g/mol Electron configuration perhaps [Rn] 5f14 6d9 7s1 (guess based on platinum) Electrons per shell 2, 8, 18, 32, 32, 17... General Name, Symbol, Number roentgenium, Rg, 111 Chemical series transition metals Group, Period, Block 11, 7, d Appearance unknown, probably yellow or orange metallic Atomic mass (284) g/mol Electron configuration perhaps [Rn] 5f14 6d10 7s1 (guess based on gold) Electrons per shell 2, 8, 18, 32, 32, 18, 1... General Name, Symbol, Number ununbium, Uub, 112 Chemical series transition metals Group, Period, Block 12, 7, d Appearance unknown, probably silvery white or metallic gray liquid Atomic mass (285) g/mol Electron configuration perhaps [Rn] 5f14 6d10 7s2 (guess based on mercury) Electrons per shell 2, 8, 18, 32, 32... General Name, Symbol, Number ununtrium, Uut, 113 Chemical series presumably poor metals Group, Period, Block 13, 7, p Appearance unknown, probably silvery white or metallic gray Atomic mass (284) g/mol Electron configuration perhaps [Rn] 5f14 6d10 7s2 7p1 (guess based on thallium) Electrons per shell 2, 8, 18, 32... General Name, Symbol, Number ununquadium, Uuq, 114 Chemical series presumably poor metals Group, Period, Block 14, 7, p Appearance unknown, probably silvery white or metallic gray Atomic mass (298) g/mol Electron configuration perhaps [Rn] 5f14 6d10 7s2 7p2 (guess based on lead) Electrons per shell 2, 8, 18, 32... General Name, Symbol, Number ununpentium, Uup, 115 Group, Period, Block 15, 7, p Atomic mass (299) g·mol−1 Electron configuration perhaps [Rn] 5f14 6d10 7s2 7p3 (guess based on bismuth) Electrons per shell 2, 8, 18, 32, 32, 18, 5 CAS registry number 54085-64-2 Selected isotopes References... General Name, Symbol, Number ununhexium, Uuh, 116 Chemical series presumably poor metals Group, Period, Block 16, 7, p Appearance unknown, probably silvery white or metallic gray Atomic mass (302) g/mol Electron configuration perhaps [Rn] 5f14 6d10 7s2 7p4 (guess based on polonium) Electrons per shell 2, 8, 18, 32... General Name, Symbol, Number ununseptium, Uus, 117 Chemical series presumably halogens Group, Period, Block 17, 7, p Appearance unknown, probably dark metallic Standard atomic weight predicted, (310) g·mol−1 Electron configuration perhaps [Rn] 5f14 6d10 7s2 7p5 (guess based on astatine) Electrons per shell 2, 8, 18, 32, 32... General Name, Symbol, Number ununoctium, Uuo, 118 Chemical series noble gases Group, Period, Block 18, 7, p Appearance unknown, probably colorless Atomic mass predicted, (314) g/mol Electron configuration perhaps [Rn] 5f14 6d10 7s2 7p6 (guess based on radon) Electrons per shell 2, 8, 18, 32, 32, 18, 8 Phase... The lanthanide series comprises the 15 elements from lanthanum to lutetium on the periodic table, with atomic numbers 57 through 71. ... General Name, Symbol, Number lanthanum, La, 57 Chemical series lanthanides Group, Period, Block 3, 6, f Appearance silvery white Atomic mass 138. ... General Name, Symbol, Number cerium, Ce, 58 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Standard atomic weight 140. ... General Name, Symbol, Number praseodymium, Pr, 59 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance grayish white Standard atomic weight 140. ... General Name, Symbol, Number neodymium, Nd, 60 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white, yellowish tinge Standard atomic weight 144. ... General Name, Symbol, Number promethium, Pm, 61 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance metallic Atomic mass [145](0) g/mol Electron configuration [Xe] 4f5 6s2 Electrons per shell 2, 8, 18, 23, 8, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number samarium, Sm, 62 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Atomic mass 150. ... General Name, Symbol, Number gadolinium, Gd, 64 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Standard atomic weight 157. ... General Name, Symbol, Number terbium, Tb, 65 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Atomic mass 158. ... General Name, Symbol, Number dysprosium, Dy, 66 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Standard atomic weight 162. ... General Name, Symbol, Number holmium, Ho, 67 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Atomic mass 164. ... General Name, Symbol, Number erbium, Er, 68 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Standard atomic weight 167. ... General Name, Symbol, Number thulium, Tm, 69 Chemical series lanthanides Group, Period, Block ?, 6, f Appearance silvery gray Atomic mass 168. ... Yb redirects here; for the unit of information see Yottabit General Name, Symbol, Number ytterbium, Yb, 70 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Standard atomic weight 173. ... General Name, Symbol, Number lutetium, Lu, 71 Chemical series lanthanides Group, Period, Block n/a, 6, d Appearance silvery white Standard atomic weight 174. ... The actinide (or actinoid) series encompasses the 15 chemical elements that lie between actinium and lawrencium on the periodic table, with atomic numbers 89 - 103[1]. The actinide series is named after actinium. ... General Name, Symbol, Number actinium, Ac, 89 Chemical series actinides Group, Period, Block 3, 7, f Appearance silvery Standard atomic weight (227) g·mol−1 Electron configuration [Rn] 6d1 7s2 Electrons per shell 2, 8, 18, 32, 18, 9, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number thorium, Th, 90 Chemical series Actinides Group, Period, Block n/a, 7, f Appearance silvery white Standard atomic weight 232. ... General Name, Symbol, Number protactinium, Pa, 91 Chemical series actinides Group, Period, Block n/a, 7, f Appearance bright, silvery metallic luster Standard atomic weight 231. ... This article is about the chemical element. ... General Name, Symbol, Number neptunium, Np, 93 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery metallic Standard atomic weight (237) g·mol−1 Electron configuration [Rn] 5f4 6d1 7s2 Electrons per shell 2, 8, 18, 32, 22, 9, 2 Physical properties Phase solid Density (near r. ... This article is about the radioactive element. ... General Name, Symbol, Number americium, Am, 95 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery white sometimes yellow Standard atomic weight (243) g·mol−1 Electron configuration [Rn] 5f7 7s2 Electrons per shell 2, 8, 18, 32, 25, 8, 2 Physical properties Phase solid Density (near... General Name, Symbol, Number curium, Cm, 96 Chemical series actinides Group, Period, Block ?, 7, f Appearance silvery Atomic mass (247) g/mol Electron configuration [Rn] 5f7 6d1 7s2 Electrons per shell 2, 8, 18, 32, 25, 9, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number berkelium, Bk, 97 Chemical series actinides Group, Period, Block n/a, 7, f Appearance unknown, probably silvery white or metallic gray Atomic mass (247) g·mol−1 Electron configuration [Rn] 5f9 7s2 Electrons per shell 2, 8, 18, 32, 27, 8, 2 Physical properties Phase solid... General Name, Symbol, Number californium, Cf, 98 Chemical series actinides Group, Period, Block n/a, 7, f Appearance unknown, probably silvery white or metallic gray Atomic mass (251) g·mol−1 Electron configuration [Rn] 5f10 7s2 Electrons per shell 2, 8, 18, 32, 28, 8, 2 Physical properties Phase solid... General Name, Symbol, Number einsteinium, Es, 99 Chemical series actinides Group, Period, Block n/a, 7, f Appearance unknown, probably silvery white or metallic gray Standard atomic weight (252) g·mol−1 Electron configuration [Rn] 5f11 7s2 Electrons per shell 2, 8, 18, 32, 29, 8, 2 Physical properties Phase... General Name, Symbol, Number fermium, Fm, 100 Chemical series actinides Group, Period, Block n/a, 7, f Appearance unknown, probably silvery white or metallic gray Atomic mass (257) g·mol−1 Electron configuration [Rn] 5f12 7s2 Electrons per shell 2, 8, 18, 32, 30, 8, 2 Physical properties Phase solid... General Name, Symbol, Number mendelevium, Md, 101 Chemical series actinides Group, Period, Block n/a, 7, f Appearance unknown, probably silvery white or metallic gray Atomic mass (258) g·mol−1 Electron configuration [Rn] 5f13 7s2 Electrons per shell 2, 8, 18, 32, 31, 8, 2 Physical properties Phase solid... General Name, Symbol, Number nobelium, No, 102 Chemical series actinides Group, Period, Block n/a, 7, f Appearance unknown, probably silvery white or metallic gray Atomic mass (259) g/mol Electron configuration [Rn] 5f14 7s2 Electrons per shell 2, 8, 18, 32, 32, 8, 2 Physical properties Phase solid Melting... General Name, Symbol, Number lawrencium, Lr, 103 Chemical series actinides Group, Period, Block n/a, 7, d Appearance unknown, probably silvery white or metallic gray Atomic mass (264) g·mol−1 Electron configuration probably [Rn] 5f14 7s2 7p1 Electrons per shell 2, 8, 18, 32, 32, 8, 3 Physical properties... The f-block of the periodic table of elements consists of those elements for which, in the atomic ground state, the highest-energy electrons occupy f-orbitals. ... This is a version of the periodic table of the elements that places all elements in the same rows. ... The f-block of the periodic table of elements consists of those elements for which, in the atomic ground state, the highest-energy electrons occupy f-orbitals. ... An extended periodic table was suggested by Glenn T. Seaborg in 1969. ... The g-block of the periodic table of the elements consists of those elements for which, in the atomic ground state, the highest-energy electrons occupy g-orbitals. ...


Notes

  • Lanthanides are also known as "rare earth elements", a deprecated term. Regarding group membership of these elements, see here.
  • Alkali metals, alkaline earth metals, transition metals, actinides, lanthanides, and poor metals are all collectively known as "metals".
  • Halogens and noble gases are also non-metals.

Chemical series of the periodic table The lanthanide series comprises the 15 elements from lanthanum to lutetium on the periodic table, with atomic numbers 57 through 71. ... Rare earth ore Rare earth elements and rare earth metals are trivial names sometimes applied to a collection of 17 chemical elements in the periodic table, namely scandium, yttrium, and the lanthanides. ... A periodic table group is a vertical column in the periodic table of the chemical elements. ... 6 *Lanthanides 7 **Actinides IUPAC has not recommended a specific format for the periodic table, so different conventions are permitted and are often used for the group number of lanthanides and actinides. ... This article is about metallic materials. ... sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex sex...

     Alkali metals      Alkaline earth metals      Lanthanides      Actinides      Transition metals      Poor metals      Metalloids      Nonmetals      Halogens      Noble gases The alkali metals are a series of elements comprising Group 1 (IUPAC style) of the periodic table: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). ... The alkaline earth metals are a series of elements comprising Group 2 (IUPAC style) of the periodic table: beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba) and radium (Ra). ... The lanthanide series comprises the 15 elements from lanthanum to lutetium on the periodic table, with atomic numbers 57 through 71. ... The actinide (or actinoid) series encompasses the 15 chemical elements that lie between actinium and lawrencium on the periodic table, with atomic numbers 89 - 103[1]. The actinide series is named after actinium. ... In chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings: It commonly refers to any element in the d-block of the periodic table, including zinc, cadmium and mercury. ... This article does not cite its references or sources. ... Metalloid is a term used in chemistry when classifying the chemical elements. ... Together with the metals and metalloids, a nonmetal is one of three categories of chemical elements as distinguished by ionization and bonding properties. ... This article is about the chemical series. ... This article is about the chemical series. ...

State at standard temperature and pressure (0 °C and 1 atm)
Gases Liquids Solids
Natural occurrence
Undiscovered Synthetic From decay Primordial

Temperature and air pressure can vary from one place to another on the Earth, and can also vary in the same place with time. ...

Alternative versions (Layout/view of the table)

Other alternative periodic tables exist. This is a standard display of the periodic table of the elements. ... The alternate table is a periodic table perpendicularly rotated counterclockwise, hence like in many writing systems, the lower groups are to the left and the number increases to the right. ... Category: ... This large version of the periodic table contains the symbol, name, atomic number, and standard atomic weight of each element. ... Stylized lithium-7 atom: 3 protons, 4 neutrons & 3 electrons (~1800 times smaller than protons/neutrons). ... The Detailed Table is a smaller version of the Huge Table. ... Electronegativity is a measure of the ability of an atom or molecule to attract electrons in the context of a chemical bond. ... This is a version of the periodic table of the elements that places all elements in the same rows. ... The lanthanide series comprises the 15 elements from lanthanum to lutetium on the periodic table, with atomic numbers 57 through 71. ... The actinide (or actinoid) series encompasses the 15 chemical elements that lie between actinium and lawrencium on the periodic table, with atomic numbers 89 - 103[1]. The actinide series is named after actinium. ... electron numbers indicate subshells that are filled to their maximum. ... Color coding for atomic numbers: Elements numbered in blue are liquids at Standard Temperature and Pressure (STP); those in green are gases at STP; those in black are solid at STP; those in red are synthetic (all are solid at STP). ... Color coding for atomic numbers: Elements numbered in blue are liquids at Standard Temperature and Pressure (STP); those in green are gases at STP; those in black are solid at STP; those in red are synthetic (all are solid at STP). ... In chemistry, valence, also known as valency or valency number, is a measure of the number of chemical bonds formed by the atoms of a given element. ... Alternative periodic tables are chemical element displays different from the well known Mendeleev periodic table. ...


Arrangement

The layout of the periodic table demonstrates recurring ("periodic") chemical properties. Elements are listed in order of increasing atomic number (i.e. the number of protons in the atomic nucleus). Rows are arranged so that elements with similar properties fall into the same vertical columns ("groups"). According to quantum mechanical theories of electron configuration within atoms, each horizontal row ("period") in the table corresponded to the filling of a quantum shell of electrons. There are progressively longer periods further down the table, grouping the elements into s-, p-, d- and f-blocks to reflect their electron configuration. See also: List of elements by atomic number In chemistry and physics, the atomic number (also known as the proton number) is the number of protons found in the nucleus of an atom. ... For other uses, see Proton (disambiguation). ... The nucleus of an atom is the very small dense region, of positive charge, in its centre consisting of nucleons (protons and neutrons). ... For a less technical and generally accessible introduction to the topic, see Introduction to quantum mechanics. ... For other uses, see Electron (disambiguation). ...


In printed tables, each element is usually listed with its element symbol and atomic number; many versions of the table also list the element's atomic mass and other information, such as its abbreviated electron configuration, electronegativity and most common valence numbers. A chemical symbol is an abbreviation or short representation of the name of a chemical element. ... See also: List of elements by atomic number In chemistry and physics, the atomic number (also known as the proton number) is the number of protons found in the nucleus of an atom. ... Stylized lithium-7 atom: 3 protons, 4 neutrons & 3 electrons (~1800 times smaller than protons/neutrons). ... Electron atomic and molecular orbitals In atomic physics and quantum chemistry, the electron configuration is the arrangement of electrons in an atom, molecule, or other physical structure (, a crystal). ... Electronegativity is a measure of the ability of an atom or molecule to attract electrons in the context of a chemical bond. ... It has been suggested that this article or section be merged into Valence (chemistry). ...


As of 2006, the table contains 117 chemical elements whose discoveries have been confirmed. Ninety-two are found naturally on Earth, and the rest are synthetic elements that have been produced artificially in particle accelerators. Elements 43 (technetium) and 61 (promethium), although of lower atomic number than the naturally occurring element 92, uranium, are synthetic; elements 93 (neptunium) and 94 (plutonium) are listed with the synthetic elements, but have been found in trace amounts on earth. 2006 is a common year starting on Sunday of the Gregorian calendar. ... The chemical elements labeled as synthetic are unstable, with a half-life so short (ranging from a fraction of millisecond to a few million years) relative to the age of the Earth that any atoms of that element that may have been present when the Earth formed have long since... A particle accelerator uses electric fields to propel charged particles to great energies. ...


Periodicity of chemical properties

The main value of the periodic table is the ability to predict the chemical properties of an element based on its location on the table. It should be noted that the properties vary differently when moving vertically along the columns of the table, than when moving horizontally along the rows.


Groups and periods

  • A group is a vertical column in the periodic table of the elements.

Groups are considered the most important method of classifying the elements. In some groups, the elements have very similar properties and exhibit a clear trend in properties down the group — these groups tend to be given trivial (unsystematic) names, e.g. the alkali metals, alkaline earth metals, halogens and noble gases. Some other groups in the periodic table display fewer similarities and/or vertical trends (for example Groups 14 and 15), and these have no trivial names and are referred to simply by their group numbers. A periodic table group is a vertical column in the periodic table of the chemical elements. ... The alkali metals are a series of elements comprising Group 1 (IUPAC style) of the periodic table: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). ... The alkaline earth metals are the series of elements in Group 2 of the periodic table: beryllium, magnesium, calcium, strontium, barium and radium (not always considered due to its very short half-life). ... This article is about the chemical series. ... This article is about the chemical series. ...

  • A period is a horizontal row in the periodic table of the elements.

Although groups are the most common way of classifying elements, there are some regions of the periodic table where the horizontal trends and similarities in properties are more significant than vertical group trends. This can be true in the d-block (or "transition metals"), and especially for the f-block, where the lanthanides and actinides form two substantial horizontal series of elements. In the periodic table of the elements, a period is a row of the table. ... D Block is a rap group based in Yonkers, New York. ... In chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings: It commonly refers to any element in the d-block of the periodic table, including zinc, cadmium and mercury. ... The f-block of the periodic table of elements consists of those elements for which, in the atomic ground state, the highest-energy electrons occupy f-orbitals. ... The lanthanide series is the 14 rare earth chemical elements which lie between lanthanum and ytterbium on the periodic table. ... The actinide series encompasses the 14 chemical elements that lie between actinium and nobelium on the periodic table with atomic numbers 89 - 102 inclusive. ...


Periodic trends of groups

Modern quantum mechanical theories of atomic structure explain group trends by proposing that elements within the same group have the same electron configurations in their valence shell, which is the most important factor in accounting for their similar properties. Elements in the same group also show patterns in their atomic radius, ionization energy, and electronegativity. From top to bottom in a group, the atomic radii of the elements increase. Since there are more filled energy levels, electrons are found farther from the nucleus. From the top, each successive element has a lower ionization energy because it is easier to remove an electron since the atoms are less tightly bound. Similarly, a group will also see a top to bottom decrease in electronegativity due to an increasing distance between valence electrons and the nucleus. For a less technical and generally accessible introduction to the topic, see Introduction to quantum mechanics. ... The valence shell is the outermost shell of an atom, which contains the electrons most likely to account for the nature of any reactions involving the atom and of the bonding interactions it has with other atoms. ... Atomic radius: Ionic radius Covalent radius Metallic radius van der Waals radius edit Atomic radius, and more generally the size of an atom, is not a precisely defined physical quantity, nor is it constant in all circumstances. ... The ionization energy (IE) of an atom or of a molecule is the energy required to strip it of an electron. ... Electronegativity is a measure of the ability of an atom or molecule to attract electrons in the context of a chemical bond. ...


Periodic trends of periods

Elements in the same period show trends in atomic radius, ionization energy, electron affinity, and electronegativity. Moving left to right across a period, atomic radius usually decreases. This occurs because each successive element has an added proton and electron which causes the electron to be drawn closer to the nucleus. This decrease in atomic radius also causes the ionization energy to increase when moving from left to right across a period. The more tightly bound an element is, the more energy is required to remove an electron. Similarly, electronegativity will increase in the same manner as ionization energy because of the amount of pull that is exerted on the electrons by the nucleus. Electron affinity also shows a slight trend across a period. Metals (left side of a period) generally have a lower electron affinity than nonmetals (right side of a period) with the exception of the noble gases. Atomic radius: Ionic radius Covalent radius Metallic radius van der Waals radius edit Atomic radius, and more generally the size of an atom, is not a precisely defined physical quantity, nor is it constant in all circumstances. ... The ionization energy (IE) of an atom or of a molecule is the energy required to strip it of an electron. ... The electron affinity, Eea, of an atom or molecule is the energy required to detach an electron from a singly charged negative ion, i. ... Electronegativity is a measure of the ability of an atom or molecule to attract electrons in the context of a chemical bond. ... The electron affinity, Eea, of an atom or molecule is the energy required to detach an electron from a singly charged negative ion, i. ...


Examples

Noble gases

All the elements of Group 18, the noble gases, have full valence shells. This means they do not need to react with other elements to attain a full shell, and are therefore much less reactive than other groups. Helium is the most inert element among noble gases, since reactivity, in this group, increases with the periods: it is possible to make heavy noble gases react since they have much larger electron shells. However, their reactivity remains low in absolute terms. The noble gases are a chemical series. ... For other uses, see Helium (disambiguation). ... In English, to be inert is to be in a state of doing little or nothing. ...


Halogens

In Group 17, known as the halogens, elements are missing just one electron each to fill their shells. Therefore, in chemical reactions they tend to acquire electrons (the tendency to acquire electrons is called electronegativity). This property is most evident for fluorine (the most electronegative element of the whole table), and it diminishes with increasing period. This article is about the chemical series. ... Electronegativity is a measure of the ability of an atom or molecule to attract electrons in the context of a chemical bond. ... Distinguished from fluorene and fluorone. ...


As a result, all halogens form acids with hydrogen, such as hydrofluoric acid, hydrochloric acid, hydrobromic acid and hydroiodic acid, all in the form HX. Their acidity increases with higher period, for example, with regard to iodine and fluorine, since a large I- ion is more stable in solution than a small F-, there is less volume in which to disperse the charge. R-phrases , S-phrases , , , , Flash point nonflammable Related Compounds Other anions Hydrochloric acid Hydrobromic acid Hydroiodic acid Related compounds Hydrogen fluoride fluorosilicic acid Supplementary data page Structure and properties n, εr, etc. ... R-phrases , S-phrases , , Flash point Non-flammable. ... It has been suggested that this article or section be merged into hydrogen bromide. ... Hydroiodic acid (sometimes also spelled hydriodic acid) is a highly acidic aqueous solution of hydrogen iodide (HI) (Concentrated solution is usually 48 - 57% HI). ... Acidity is a controversial novelette written for the popular South Asian website Chowk. ... This article is about the electrically charged particle. ...


Transition metals

For the transition metals (Groups 3 to 12), horizontal trends across periods are often important as well as vertical trends down groups; the differences between groups adjacent are usually not dramatic. Transition metal reactions often involve coordinated species. In chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings: It commonly refers to any element in the d-block of the periodic table, including zinc, cadmium and mercury. ...


Lanthanides and actinides

The chemical properties of the lanthanides (elements 57-71) and the actinides (elements 89-103) are even more similar to each other than the transition metals, and separating a mixture of these can be very difficult. This is important in the chemical purification of uranium concerning nuclear power. The lanthanide series comprises the 15 elements from lanthanum to lutetium on the periodic table, with atomic numbers 57 through 71. ... The actinide (or actinoid) series encompasses the 15 chemical elements that lie between actinium and lawrencium on the periodic table, with atomic numbers 89 - 103[1]. The actinide series is named after actinium. ... In chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings: It commonly refers to any element in the d-block of the periodic table, including zinc, cadmium and mercury. ... This article is about the chemical element. ... This article is about applications of nuclear fission reactors as power sources. ...


Structure of the periodic table

The primary determinant of an element's chemical properties is its electron configuration, particularly the valence shell electrons. For instance, any atoms with four valence electrons occupying p orbitals will exhibit some similarity. The type of orbital in which the atom's outermost electrons reside determines the "block" to which it belongs. The number of valence shell electrons determines the family, or group, to which the element belongs. Electron atomic and molecular orbitals In atomic physics and quantum chemistry, the electron configuration is the arrangement of electrons in an atom, molecule, or other physical structure (, a crystal). ... The valence shell is the outermost shell of an atom, which contains the electrons most likely to account for the nature of any reactions involving the atom and of the bonding interactions it has with other atoms. ... The valence shell is the outermost shell of an atom, which contains the electrons most likely to account for the nature of any reactions involving the atom and of the bonding interactions it has with other atoms. ...


The total number of electron shells an atom has determines the period to which it belongs. Each shell is divided into different subshells, which as atomic number increases are filled in roughly this order (the Aufbau principle): Example of a sodium electron shell model An electron shell, also known as a main energy level, is a group of atomic orbitals with the same value of the principal quantum number n. ... Electron atomic and molecular orbitals The Aufbau principle from German Aufbau meaning buildup (also Aufbau rule or building-up principle), is used to determine the electron configuration of an atom, molecule or ion. ...

Subshell: S G F D P
Period
1 1s
2 2s 2p
3 3s 3p
4 4s 3d 4p
5 5s 4d 5p
6 6s 4f 5d 6p
7 7s 5f 6d 7p
8 8s 5g 6f 7d 8p

Hence the structure of the table. Since the outermost electrons determine chemical properties, those with the same number of valence electrons are grouped together.


Progressing through a group from lightest element to heaviest element, the outer-shell electrons (those most readily accessible for participation in chemical reactions) are all in the same type of orbital, with a similar shape, but with increasingly higher energy and average distance from the nucleus. For instance, the outer-shell (or "valence") electrons of the first group, headed by hydrogen, all have one electron in an s orbital. In hydrogen, that s orbital is in the lowest possible energy state of any atom, the first-shell orbital (and represented by hydrogen's position in the first period of the table). In francium, the heaviest element of the group, the outer-shell electron is in the seventh-shell orbital, significantly further out on average from the nucleus than those electrons filling all the shells below it in energy. As another example, both carbon and lead have four electrons in their outer shell orbitals. This article is about the chemistry of hydrogen. ... General Name, Symbol, Number francium, Fr, 87 Chemical series alkali metals Group, Period, Block 1, 7, s Appearance metallic Standard atomic weight (223) g·mol−1 Electron configuration [Rn] 7s1 Electrons per shell 2, 8, 18, 32, 18, 8, 1 Physical properties Phase  ? solid Density (near r. ...


Note that as atomic number (i.e. charge on the atomic nucleus) increases, this leads to greater spin-orbit coupling between the nucleus and the electrons, reducing the validity of the quantum mechanical orbital approximation model, which considers each atomic orbital as a separate entity. See also: List of elements by atomic number In chemistry and physics, the atomic number (also known as the proton number) is the number of protons found in the nucleus of an atom. ... The nucleus of an atom is the very small dense region, of positive charge, in its centre consisting of nucleons (protons and neutrons). ... ...


Because of the importance of the outermost shell, the different regions of the periodic table are sometimes referred to as periodic table blocks, named according to the sub-shell in which the "last" electron resides, e.g. the s-block, the p-block, the d-block, etc. A block of the periodic table of elements is a set of adjacent groups. ...


Regarding the elements Ununbium, ununtrium, ununquadium, etc., they are elements that have been discovered, but so far have not been named.


History

Main article: History of the periodic table

In Ancient Greece, the influential Greek philosopher Aristotle proposed that there were four main elements: air, fire, earth and water. All of these elements could be reacted to create another one; e.g., earth and fire combined to form lava. However, this theory was dismissed when the real chemical elements started being discovered. Scientists needed an easily accessible, well organized database with which information about the elements could be recorded and accessed. This was to be known as the periodic table. The periodic table is a tabular method of displaying the chemical elements. ... For other uses, see Aristotle (disambiguation). ...


The original table was created before the discovery of subatomic particles or the formulation of current quantum mechanical theories of atomic structure. If one orders the elements by atomic mass, and then plots certain other properties against atomic mass, one sees an undulation or periodicity to these properties as a function of atomic mass. The first to recognize these regularities was the German chemist Johann Wolfgang Döbereiner who, in 1829, noticed a number of triads of similar elements: Helium atom (not to scale) Showing two protons (red), two neutrons (green) and a probability cloud (gray) of two electrons (yellow). ... For a less technical and generally accessible introduction to the topic, see Introduction to quantum mechanics. ... Properties For alternative meanings see atom (disambiguation). ... Stylized lithium-7 atom: 3 protons, 4 neutrons & 3 electrons (~1800 times smaller than protons/neutrons). ... Johann Wolfgang Döbereiner Johann Wolfgang Döbereiner (December 13, 1780 – March 24, 1849) was a German chemist. ...

Some triads
Element Molar mass
(g/mol)
Density
(g/cm³)
chlorine 35.453 0.0032
bromine 79.904 3.1028
iodine 126.90447 4.933
 
calcium 40.078 1.55
strontium 87.62 2.54
barium 137.327 3.594

In 1829 Döbereiner proposed the Law of Triads: The middle element in the triad had atomic weight that was the average of the other two members. The densities of some triads followed a similar pattern. Soon other scientists found chemical relationships extended beyond triads. Fluorine was added to Cl/Br/I group; sulfur, oxygen, selenium and tellurium were grouped into a family; nitrogen, phosphorus, arsenic, antimony, and bismuth were classified as another group.

Dmitri Mendeleev, father of the periodic table
Dmitri Mendeleev, father of the periodic table

This was followed by the English chemist John Newlands, who noticed in 1865 that when placed in order of increasing atomic weight, elements of similar physical and chemical properties recurred at intervals of eight, which he likened to the octaves of music, though his law of octaves was ridiculed by his contemporaries.[2] However, while successful for some elements, Newlands' law of octaves failed for two reasons: Image File history File links Download high resolution version (551x707, 27 KB)Repins portrait of Mendeleyev (1885) This image is in the public domain because its copyright has expired in the United States and those countries with a copyright term of life of the author plus 100 years or... Image File history File links Download high resolution version (551x707, 27 KB)Repins portrait of Mendeleyev (1885) This image is in the public domain because its copyright has expired in the United States and those countries with a copyright term of life of the author plus 100 years or... John Alexander Reina Newlands (November 26, 1838 - July 29, 1898) was an English analytical chemist who prepared in 1863 the first periodic table of the elements arranged in order of relative atomic masses, and pointed out in 1865 the law of octaves whereby every eighth element has similar properties. ... For other uses, see Octave (disambiguation). ...

  1. It was not valid for elements that had atomic masses higher than Ca.
  2. When further elements were discovered, such as the noble gases (He, Ne, Ar), they could not be accommodated in his table.

Finally, in 1869 the Russian chemistry professor Dmitri Ivanovich Mendeleev and four months later the German Julius Lothar Meyer independently developed the first periodic table, arranging the elements by mass. However, Mendeleev plotted a few elements out of strict mass sequence in order to make a better match to the properties of their neighbors in the table, corrected mistakes in the values of several atomic masses, and predicted the existence and properties of a few new elements in the empty cells of his table. Mendeleev was later vindicated by the discovery of the electronic structure of the elements in the late 19th and early 20th century. Portrait of Dmitri Mendeleev by Ilya Repin (Russian: , Dmitri Ivanovich Mendeleev  ) (8 February [O.S. 27 January] 1834 in Tobolsk – 2 February [O.S. 20 January] 1907 in Saint Petersburg), was a Russian chemist and inventor. ... Julius Lothar Meyer Julius Lothar Meyer (August 19, 1830 - April 11, 1895) was born in Varel, at that time belonging to the duchy of Oldenburg, now part of Germany. ... Alternative meaning: Nineteenth Century (periodical) (18th century — 19th century — 20th century — more centuries) As a means of recording the passage of time, the 19th century was that century which lasted from 1801-1900 in the sense of the Gregorian calendar. ...


Earlier attempts to list the elements to show the relationships between them (for example by Newlands) had usually involved putting them in order of atomic mass. Mendeleev's key insight in devising the periodic table was to lay out the elements to illustrate recurring ("periodic") chemical properties (even if this meant some of them were not in mass order), and to leave gaps for "missing" elements. Mendeleev used his table to predict the properties of these "missing elements", and many of them were indeed discovered and fit the predictions well. John Alexander Reina Newlands (November 26, 1838 - July 29, 1898) was an English analytical chemist who prepared in 1863 the first periodic table of the elements arranged in order of relative atomic masses, and pointed out in 1865 the law of octaves whereby every eighth element has similar properties. ... Stylized lithium-7 atom: 3 protons, 4 neutrons & 3 electrons (~1800 times smaller than protons/neutrons). ...


With the development of theories of atomic structure (for instance by Henry Moseley) it became apparent that Mendeleev had listed the elements in order of increasing atomic number (i.e. the net amount of positive charge on the atomic nucleus). This sequence is nearly identical to that resulting from ascending atomic mass. Properties For alternative meanings see atom (disambiguation). ... This article is about the physicist; for the naturalist see Henry Nottidge Moseley Henry Moseley at work. ... See also: List of elements by atomic number In chemistry and physics, the atomic number (also known as the proton number) is the number of protons found in the nucleus of an atom. ... The nucleus of an atom is the very small dense region, of positive charge, in its centre consisting of nucleons (protons and neutrons). ...


In order to illustrate recurring properties, Mendeleev began new rows in his table so that elements with similar properties fell into the same vertical columns ("groups").


With the development of modern quantum mechanical theories of electron configuration within atoms, it became apparent that each horizontal row ("period") in the table corresponded to the filling of a quantum shell of electrons. In Mendeleev's original table, each period was the same length. Modern tables have progressively longer periods further down the table, and group the elements into s-, p-, d- and f-blocks to reflect our understanding of their electron configuration. For a less technical and generally accessible introduction to the topic, see Introduction to quantum mechanics. ... For other uses, see Electron (disambiguation). ...


In the 1940s Glenn T. Seaborg identified the transuranic lanthanides and the actinides, which may be placed within the table, or below (as shown above). Glenn Theodore Seaborg (April 19, 1912 – February 25, 1999) won the 1951 Nobel Prize in Chemistry for discoveries in the chemistry of the transuranium elements,[1] contributed to the discovery and isolation of ten elements, developed the actinide concept and was the first to propose the actinide series which led... This article needs additional references or sources to facilitate its verification. ...


See also

This is a table of electron configurations of atoms. ... This isotope table shows all of the known isotopes of the chemical elements, arranged with increasing atomic numbers (proton numbers) from left to right and increasing neutron numbers from top to bottom. ... These isotope tables show all of the known isotopes of the chemical elements, arranged with increasing atomic number from left to right and increasing neutron number from top to bottom. ... The discovery of the elements known to exist today is presented here in chronological order. ... The abundance of a chemical element measures how relatively common the element is, or how much of the element there is by comparison to all other elements. ... IUPAC logo The International Union of Pure and Applied Chemistry (IUPAC) (Pronounced as eye-you-pack) is an international non-governmental organization established in 1919 devoted to the advancement of chemistry. ... In chemistry, heavy transuranic elements receive a permanent trivial name and symbol only after their synthesis has been confirmed. ... In cosmochemistry, the Cosmochemical Periodic Table of the Elements in the Solar System is a periodic table that lists all known chemical elements. ... A table of chemical elements ordered by atomic number. ... In group theory in mathematics, a periodic group is a group in which each element has finite order. ... An extended periodic table was suggested by Glenn T. Seaborg in 1969. ... Below is a periodic table using Chinese characters as symbols for chemical elements. ... Thomas Andrew Tom Lehrer (born April 9, 1928) is an American singer-songwriter, satirist, pianist, and mathematician. ... The Elements (1959) is a song by musical humorist Tom Lehrer, which recites the names of all the chemical elements known at the time of writing, up to number 102, nobelium. ... Peter Schickele (born Johann Peter Schickele, July 17, 1935) is an American composer, musical educator and parodist, perhaps best known for his comedy music albums featuring music he wrote as P. D. Q. Bach. ...

References

  1. ^ IUPAC article on periodic table
  2. ^ Bryson, Bill (2004). A Short History of Nearly Everything. London: Black Swan, 687. ISBN 9780552151740.  pp141-2
  • Theodore L. Brown, H. Eugene LeMay, and Bruce E. Bursten (2005). Chemistry:The Central Science, 10th edition, Prentice Hall. ISBN 0-13-109686-9. 
  • Helmenstine, Marie (2007). Trends in the Periodic Table. About, Inc.. Retrieved on 2007-01-27.

William Bill McGuire Bryson, OBE, (born December 8, 1951) is a best-selling American-born author of humorous books on travel, as well as books on the English language and on scientific subjects. ... A Short History of Nearly Everything by Bill Bryson A Short History of Nearly Everything (ISBN 0-7679-0817-1) is a general science book by Bill Bryson, which explains some areas of science in ordinary language. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 27th day of the year in the Gregorian calendar. ...

Further reading

  • Scerri, E.R., references to several scholarly articles by this author.
  • Mazurs, E.G., "Graphical Representations of the Periodic System During One Hundred Years". University of Alabama Press, Alabama. 1974.
  • Bouma, J., "An Application-Oriented Periodic Table of the Elements", J. Chem. Ed., 66, 741 (1989).
  • Eric R. Scerri, The Periodic Table: Its Story and Its Significance, Oxford University Press, 2006.

External links

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  Results from FactBites:
 
Chemistry: WebElements Periodic Table (426 words)
The periodic "law" of chemistry recognises that many properties of the chemical elements are periodic functions of their atomic number (the number of protons within the element's atomic nucleus).
The periodic table is an arrangement of the chemical elements ordered by atomic number in columns (groups) and rows (periods) presented so as to emphasize their periodic properties.
The relative merits of various other periodic table organisations is still the subject of debate.
Periodic Table - MSN Encarta (1194 words)
Periodic Table, table of the chemical elements arranged to illustrate patterns of recurring chemical and physical properties.
The periodic table has been published in various shapes and sizes, but the most commonly used modern form begins with a column of group 1 metals on the left-hand side, followed by a column of group 2 alkaline earth metals.
A number of chemists contributed to the development of the periodic table during the 19th century; however, Mendeleyev is regarded as the primary discoverer.
  More results at FactBites »

 
 

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