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Encyclopedia > Valence (chemistry)

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. Over the last century, the concept of valence evolved into a range of approaches for describing the chemical bond, including Lewis structures (1916), valence bond theory (1927), molecular orbitals (1928), valence shell electron pair repulsion theory (1958) and all the advanced methods of quantum chemistry. Valence is a scientific term in chemistry to describe electrons in the outermost orbital. ... For other uses, see Chemistry (disambiguation). ... A chemical bond is the physical process responsible for the attractive interactions between atoms and molecules, and that which confers stability to diatomic and polyatomic chemical compounds. ... Properties For other meanings of Atom, see Atom (disambiguation). ... 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. ... G. N. Lewis Lewis structures, also called electron-dot structures or electron-dot diagrams, are diagrams that show the bonding between atoms of a molecule, and the lone pairs of electrons that may exist in the molecule [1] [2]. A Lewis structure can be drawn for any covalently-bonded molecule... In chemistry, valence bond theory explains the nature of a chemical bond in a molecule in terms of atomic valencies. ... In chemistry, a molecular orbital is a region in which an electron may be found in a molecule. ... Valence shell electron pair repulsion theory (VSEPR) (1957) is a model in chemistry that aims to generally represent the shapes of individual molecules [1] . To achieve this, it is necessary to construct a valid Lewis structure that shows all of the bonds within the molecule and the locations of lone... Quantum chemistry is a branch of theoretical chemistry, which applies quantum mechanics and quantum field theory to address issues and problems in chemistry. ...

Contents

History

The etymology of the word "valence" is from 1425, meaning "extract, preparation," from Latin valentia "strength, capacity," and the chemical meaning referring to the "combining power of an element" is recorded from 1884, from German Valenz.[1] Etymologies redirects here. ...


In 1789, William Higgins published views on what he called combinations of "ultimate" particles, which foreshadowed the concept of valency bonds.[2] If, for example, according to Higgins, the force between the ultimate particle of oxygen and the ultimate particle of nitrogen were 6, then the strength of the force would be divided accordingly, and similarly for the other combinations of ultimate particles: William Higgins (1763-1825), an Irish chemist, was one of the early proponents of atomic theory, on whose works John Dalton is said to have based much of his work. ... In chemistry, valence bond theory explains the nature of a chemical bond in a molecule in terms of atomic valencies. ...

William Higgins' combinations of ultimate particles (1789)
William Higgins' combinations of ultimate particles (1789)

The exact inception, however, of the theory of chemical valencies can be traced to an 1852 paper by Edward Frankland, in which he combined the older theories of free radicals and “type theory” with thoughts on chemical affinity to show that certain elements have the tendency to combine with other elements to form compounds containing 3, i.e. in the three atom groups (e.g. NO3, NH3, NI3, etc.) or 5, i.e. in the five atom groups (e.g. NO5, NH4O, PO5, etc.), equivalents of the attached elements. It is in this manner, according to Franklin, that their affinities are best satisfied. Following these examples and postulates, Franklin declares how obvious it is that:[3] Image File history File links Download high-resolution version (1180x618, 197 KB) Date: 1789; Author: William Higgins; Published in: A Comparative View of the Phlogistic and Antiphlogistic Theories. ... Image File history File links Download high-resolution version (1180x618, 197 KB) Date: 1789; Author: William Higgins; Published in: A Comparative View of the Phlogistic and Antiphlogistic Theories. ... William Higgins (1763-1825), an Irish chemist, was one of the early proponents of atomic theory, on whose works John Dalton is said to have based much of his work. ... Sir Edward Frankland (January 18, 1825 – August 9, 1899) was an English chemist. ... In chemistry free radicals are uncharged atomic or molecular species with unpaired electrons or an otherwise open shell configuration. ... Chemical affinity results from electronic properties by which dissimilar substances are capable of forming chemical compounds. ...

A tendency or law prevails (here), and that, no matter what the characters of the uniting atoms may be, the combining power of the attracting element, if I may be allowed the term, is always satisfied by the same number of these atoms.

This “combining power” was afterwards called quantivalence or valency (and valence by American chemists).[2]


Overview

The concept was developed in the middle of the nineteenth century in an attempt to rationalize the formulae of different chemical compounds. In 1919, Irving Langmuir, borrowed the term to explain Gilbert N. Lewis's cubical atom model by stating that "the number of pairs of electrons which any given atom shares with the adjacent atoms is called the covalence of that atom." The prefix co-, e.g. co-author, means together, jointly, associated in action, partnered to a lesser degree, etc.,; thus a co-valent bond, essentially, means that the atoms share valence. Hence, if an atom, for example, had a +1 valence, meaning it was missing an electron, and another a -1 valence, meaning it had an extra electron, then a bond between these two atoms would result because they would be complementing or sharing their out of balance valence tendencies. Subsequently, it is now more common to speak of covalent bonds rather than "valence", which has fallen out of use in higher level work with the advances in the theory of chemical bonding, but is still widely used in elementary studies where it provides a heuristic introduction to the subject. A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... Look up chemical compound in Wiktionary, the free dictionary. ... Irving Langmuir (January 31, 1881 in Brooklyn, New York - August 16, 1957 in Woods Hole, Massachusetts) was an American chemist and physicist. ... Lewis in the Berkeley Lab Gilbert Newton Lewis (October 23, 1875-March 23, 1946) was a famous American physical chemist. ... The cubical atom was an early atomic model developed by Gilbert N. Lewis in 1916 to account for the phenomenon of valency. ... For other uses, see Electron (disambiguation). ... Covalent redirects here. ...


"Number of bonds" definition

The number of bonds formed by a given element was originally thought to be a fixed chemical property and in fact, in many cases, this is a good approximation. For example, in many of their compounds, carbon forms four bonds, oxygen two and hydrogen one. However it soon became apparent that, for many elements, the valence could vary between different compounds. One of the first examples to be identified was phosphorus, which sometimes behaves as if it has a valence of three and sometimes as if it has a valence of five. One method around this problem is to specify the valence for each individual compound: although it removes much of the generality of the concept, this approach has given rise to the idea of oxidation numbers (used in Stock nomenclature) and to lambda notation in the IUPAC nomenclature of inorganic chemistry. For other uses, see Carbon (disambiguation). ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colourless (gas) colourless (liquid) Standard atomic weight 15. ... This article is about the chemistry of hydrogen. ... 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. ... Not to be confused with oxidation state. ... The IUPAC nomenclature of inorganic chemistry is a systematic method of naming inorganic chemical compounds as recommended by the International Union of Pure and Applied Chemistry (IUPAC). ...


IUPAC definition

The International Union of Pure and Applied Chemistry (IUPAC) has made several attempts to arrive at an unambiguous definition of valence. The current version, adopted in 1994,[4]: 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. ...

The maximum number of univalent atoms (originally hydrogen or chlorine atoms) that may combine with an atom of the element under consideration, or with a fragment, or for which an atom of this element can be substituted.

This definition reimposes a unique valence for each element at the expense of neglecting, in many cases, a large part of its chemistry. This article is about the chemistry of hydrogen. ... General Name, symbol, number chlorine, Cl, 17 Chemical series halogens Group, period, block 17, 3, p Appearance yellowish green Standard atomic weight 35. ...


The mention of hydrogen and chlorine is for historic reasons, although both in practice mostly form compounds in which their atoms form a single bond. Exceptions in the case of hydrogen include the ion [HF2] and the various boron hydrides such as diborane: these are examples of three-center two-electron bonds. Chlorine forms a number of fluoridesClF, ClF3 and ClF5—and its valence according to the IUPAC definition is hence five. Fluorine is the element for which the largest number of atoms combine with atoms of other elements: it is univalent in all compounds except the ion [H2F]+. In fact, the IUPAC definition can only be resolved by fixing the valences of hydrogen and fluorine as one, a convention which has been followed here. Diborane is a colorless gas at room temperature with a repulsive, sweet odor. ... A three-center two-electron bond is an electron deficient chemical bond where three atoms share two electrons. ... Fluoride is the ionic form of fluorine. ... Chlorine monofluoride has formula ClF. External links National Pollutant Inventory - Flouride and compounds fact sheet WebBook page for ClF Categories: | | ... Chlorine trifluoride is a colourless, very poisonous gas that condenses to a pale-yellow liquid. ... Chlorine pentafluoride has formula ClF5. ... Distinguished from fluorene and fluorone. ...


Valences of the elements

Valences for the majority of elements are based on the highest known fluoride.[5]

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

Valences of chemical elements 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. ... General Name, symbol, number helium, He, 2 Chemical series noble gases Group, period, block 18, 1, s Appearance colorless Standard atomic weight 4. ... 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. ... For other uses, see Boron (disambiguation). ... 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 colourless (gas) colourless (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 Standard atomic weight 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. ... Not to be confused with Galium. ... 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). ... This article is about the element. ... 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 (or lanthanoid) series comprises the 15 elements with atomic numbers 57 through 71, from lanthanum to lutetium[1]. All lanthanides are f-block elements, corresponding to the filling of the 4f electron shell, except for lutetium which is a d-block lanthanide. ... 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 derives its name from the first element in the series, 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... A chemical element, often called simply element, is a substance that cannot be divided or changed into different substances by ordinary chemical methods. ...

     None      One      Two      Three      Four      Five      Six      Seven

Atomic number colors show state at standard temperature and pressure (0 °C and 1 atm)
Solids Liquids Gases
Borders show natural occurrence
Primordial From decay Synthetic Undiscovered

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. ... In the physical sciences, a state of matter is one of the many ways that matter can interact with itself to form a macroscopic, homogenous phase. ... Temperature and air pressure can vary from one place to another on the Earth, and can also vary in the same place with time. ... Primordial elements are chemical elements found on the earth that have existed in their current form since before the earth was formed, according to the big bang theory. ... A trace radioisotope is a radioisotope that is naturally occurring. ... 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...

Other criticisms of the concept of valence

  • The valence of an element is not always equal to its lowest oxidation state: exceptions include ruthenium, osmium and xenon, which have valences of six (hexafluorides) but which form compounds with oxygen in the +8 oxidation state, and chlorine, which has a valence of five but a highest oxidation state of +7 (in perchlorates).
  • The concept of "combination" cannot be equated with the number of bonds formed by an atom. In lithium fluoride (which has the NaCl structure), each lithium atom is surrounded by six fluorine atoms, whereas the valence of lithium is universally taken to be one, as the formula LiF would suggest.[6]

In chemistry, the oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound. ... 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 osmium, Os, 76 Chemical series transition metals Group, Period, Block 8, 6, d Appearance silvery, blue cast Standard atomic weight 190. ... General Name, Symbol, Number xenon, Xe, 54 Chemical series noble gases Group, Period, Block 18, 5, p Appearance colorless Standard atomic weight 131. ... Perchlorates are the salts derived from perchloric acid (HClO4). ... For other uses, see LIF. Lithium fluoride is a chemical compound of lithium and fluorine. ... R-phrases 36 S-phrases none Flash point Non-flammable Related Compounds Other anions NaF, NaBr, NaI Other cations LiCl, KCl, RbCl, CsCl, MgCl2, CaCl2 Related salts Sodium acetate Supplementary data page Structure and properties n, εr, etc. ... This article is about the chemical element named Lithium. ...

See also

Chemical affinity results from electronic properties by which dissimilar substances are capable of forming chemical compounds. ...

References

  1. ^ Valence - Online Etymology Dictionary.
  2. ^ a b Partington, J.R. (1989). A Short History of Chemistry. Dover Publications, Inc. ISBN 0-486-65977-1. 
  3. ^ Franklin, E. (1852). Phil. Trans., vol. cxlii, 417.
  4. ^ Pure Appl. Chem. 66: 1175 (1994).
  5. ^ http://www.webelements.com/ (accessed 2006-02-20).
  6. ^ In the gas phase, LiF does indeed exist as discrete diatomic molecules as the valences would suggest: Cotton, F. Albert; Wilkinson, Geoffrey; Murillo, Carlos A.; Bochmann, Manfred (1999). Advanced Inorganic Chemistry (6th Edn.) New York:Wiley-Interscience. ISBN 0-471-19957-5.

Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 51st day of the year in the Gregorian calendar. ... F. Albert Cotton is the W.T. Doherty-Welch Foundation Chair and Distinguished Professor of Chemistry at Texas A&M University. ... Sir Geoffrey Wilkinson was an English chemist He was born 14 July 1921 in the village of Springside, near Todmorden in Yorkshire. ...

External links


  Results from FactBites:
 
Valency - LoveToKnow 1911 (2536 words)
The doctrine of valency, in chemistry, may be defined as the doctrine of the combining power of the atoms or elementary radicles of which compound molecules consist.
Frankland dealt more particularly with the valency of the metallic elements, in which he was specially interested at the time; but in conjunction with his co-worker Kolbe, he subsequently applied it to compounds of carbon.
A crystalline structure is regarded as a close-packed, homogeneous assemblage of the spheres of influence of the component atoms.
Mixed valency in chemistry, physics and biology (2174 words)
Steven Boxer is the Camille and Henry Dreyfus Professor in the Department of Chemistry at Stanford University.
He was the Head of Chemistry from 1985 to 1990, Chair of the Curriculum in Applied Sciences from 1994 to1997, and Vice Chancellor/Vice Provost for Graduate Studies and Research from 1994 to 1999.
Following a spell as Assistant Professor of Chemistry at the University of Crete, Greece, he returned to the UK at the University of Sussex where he was successively Lecturer (1989-1993), Reader (1993-1996) and Professor (1997-2004) of Solid State Chemistry at the School of Chemistry, Physics and Environmental Science.
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