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The electron affinity, Eea, of an atom or molecule is the energy required to detach an electron from a singly charged negative ion, i. History See also Atomic theory, Atomism The concept that matter is composed of discrete units and cannot be divided into arbitrarily tiny In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by Electric charge is a fundamental conserved property of some Subatomic particles which determines their Electromagnetic interaction. An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge e. , the energy change for the process

X- → X + e−

An equivalent definition is the energy released (Einitial − Efinal) when an electron is attached to a neutral atom or molecule. It should be noted that the sign convention for Eea is the opposite to most thermodynamic quantities: a positive electron affinity indicates that energy is released on going from atom to anion. In Physics, a sign convention is a choice of the signs (plus or minus of a set of quantities in a case where the choice of sign is arbitrary In Physics, thermodynamics (from the Greek θερμη therme meaning " Heat " and δυναμις dynamis meaning " An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge

All elements whose EA have been measured using modern methods have a positive electron affinity, but older texts mistakenly report that some elements such as alkaline earth metals have negative Eea, meaning they would repel electrons. This is not recognized by modern chemists. The electron affinity of the noble gases have not been conclusively measured, so they may or may not have slightly negative EAs. Atoms whose anions are relatively more stable than neutral atoms have a greater Eea. Chlorine most strongly attracts extra electrons; mercury most weakly attracts an extra electron. Chlorine (ˈklɔriːn from the Greek word 'χλωρóς' ( khlôros, meaning 'pale green' is the Chemical element with Atomic number 17 and Mercury (ˈmɜrkjʊri also called quicksilver or hydrargyrum, is a Chemical element with the symbol Hg ( Latinized hydrargyrum Eea of noble gases are close to 0.

Although Eea vary in a chaotic manner across the table, some patterns emerge. Generally, nonmetals have more positive Eea than metals. Nonmetal is a term used in Chemistry when classifying the Chemical elements On the basis of their general physical and chemical properties every element in the The M acro E xpansion T emplate A ttribute L anguage complements TAL, providing macros which allow the reuse of code across

Contents

Values for the elements

Main article: Electron affinity (data page)

The following data are quoted in kJ/mol. Elements Molecules The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material Elements marked with an asterisk are expected to have electron affinities close to zero on quantum mechanical grounds. Elements marked with a dotted box are synthetically made elements - elements not found naturally in the environment.

Group → 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
↓ Period
1 H
73
He
*
2 Li
60		 Be
*
B
27		 C
122		 N
*		 O
141		 F
328		 Ne
*
3 Na
53		 Mg
*
Al
42		 Si
134		 P
72		 S
200		 Cl
349		 Ar
*
4 K
48		 Ca
2		 Sc
18		 Ti
8		 V
51		 Cr
65		 Mn
*		 Fe
15		 Co
64		 Ni
112		 Cu
119		 Zn
*		 Ga
41		 Ge
119		 As
79		 Se
195		 Br
324		 Kr
*
5 Rb
47		 Sr
5		 Y
30		 Zr
41		 Nb
86		 Mo
72		 Tc
*		 Ru
101		 Rh
110		 Pd
54		 Ag
126		 Cd
*		 In
39		 Sn
107		 Sb
101		 Te
190		 I
295		 Xe
*
6 Cs
46		 Ba
14		 *
 Hf
 		 Ta
31		 W
79		 Re
*		 Os
104		 Ir
150		 Pt
205		 Au
223		 Hg
*		 Tl
36		 Pb
35		 Bi
91		 Po
 		 At
 		 Rn
*
7 Fr
 		 Ra
 		 **
 Rf
 		 Db
 		 Sg
 		 Bh
 		 Hs
 		 Mt
 		 Ds
 		 Rg
 		 Uub
 		 Uut
 		 Uuq
 		 Uup
 		 Uuh
 		 Uus
 		 Uuo
 

* Lanthanides La
45		 Ce
92		 Pr
 		 Nd
 		 Pm
 		 Sm
 		 Eu
 		 Gd
 		 Tb
 		 Dy
 		 Ho
 		 Er
 		 Tm
99		 Yb
 		 Lu
33
** Actinides Ac
 		 Th
 		 Pa
 		 U
 		 Np
 		 Pu
 		 Am
 		 Cm
 		 Bk
 		 Cf
 		 Es
 		 Fm
 		 Md
 		 No
 		 Lr
 
Chemical series of the periodic table
Alkali metals Alkaline earth metals Lanthanides Actinides Transition metals
Poor metals Metalloids Nonmetals Halogens Noble gases

Periodic trends

Eea generally increases across a period (row) in the periodic table. In Chemistry a group, also known as a family, is a vertical column in the Periodic table of the Chemical elements There are 18 groups in Trends The alkali metals show a number of trends when moving down the group - for instance decreasing electronegativity increasing reactivity and decreasing melting and boiling Biological occurrences Beryllium's low aqueous solubility means it is rarely available to biological systems it has no known role in living organisms and when encountered Occurrence Scandium yttrium and the Lanthanides (except promethium tend to occur together in the Earth's crust and are relatively abundant compared with most D-block See also Biological occurrences Of the group 5 elements only vanadium has been identified as playing a role in the biological chemistry of living systems it is involved in some of the Biological occurrences Group 6 is notable in that it contains some of the only elements in periods 5 and 6 with a known role in the biological chemistry of living organisms molybdenum See also "Group 8" redirects here For the Swedish organization see Group 8 (Sweden. Applications Alloys with other metals primarially to add corrosion and wear resistance Industrial Catalysts Superalloys Electrical Properties Group ten metals are white to light grey in color and possess a high Luster, a resistance to tarnish( Oxidation) at STP, are highly See also See also History Carbon, Tin, and Lead, are a few of the elements well known in the ancient world - together with Sulfur, Iron, See also Gold chalcogenides Periodic table Abundance Owing to their high Reactivity, the halogens are found in the environment only in compounds or as Ions Halide ions and oxoanions History Noble gas is translated from the German noun de ''Edelgas'' first used in 1898 by Hugo Erdmann to indicate their extremely low level of reactivity In the Periodic table of the elements, a period is a horizontal 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 chemical elements. Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 Helium ( He) is a colorless odorless tasteless non-toxic Inert Monatomic Chemical A period 2 element is one of the Chemical elements in the second row (or period) of the periodic table of the chemical elements. Lithium (ˈlɪθiəm is a Chemical element with the symbol Li and Atomic number 3 Beryllium (bəˈrɪliəm is a Chemical element with the symbol Be and Atomic number 4 Boron (ˈbɔərɒn is a Chemical element with Atomic number 5 and the chemical symbol B. Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Fluorine, fluorum meaning "to flow" is the Chemical element with the symbol F and Atomic number 9 Neon (ˈniːɒn is the Chemical element that has the symbol Ne and Atomic number 10 A period 3 element is one of the Chemical elements in the third row (or period) of the periodic table of the elements. Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 Magnesium (mægˈniːziəm is a Chemical element with the symbol Mg, Atomic number 12 Atomic weight 24 WikipediaNaming Silicon (ˈsɪlɪkən or /ˈsɪlɪkɒn/ silicium is the Chemical element that has the symbol Si and Atomic number 14 Phosphorus, (ˈfɒsfərəs is the Chemical element that has the symbol P and Atomic number 15 Sulfur or sulphur (ˈsʌlfɚ see spelling below) is the Chemical element that has the Atomic number 16 Chlorine (ˈklɔriːn from the Greek word 'χλωρóς' ( khlôros, meaning 'pale green' is the Chemical element with Atomic number 17 and This article pertains to the chemical element For other uses see Argon (disambiguation. A period 4 element is one of the Chemical elements in the fourth row (or period) of the periodic table of the elements. Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 Scandium (ˈskændiəm is a Chemical element that has the symbol Sc and Atomic number 21 Titanium (taɪˈteɪniəm is a Chemical element with the symbol Ti and Atomic number 22 Vanadium (vəˈneɪdiəm is a Chemical element that has the symbol V and Atomic number 23 Chromium (ˈkroʊmiəm is a Chemical element which has the symbol Cr and Atomic number 24 Manganese (ˈmæŋgəniːz is a Chemical element, designated by the symbol Mn. Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 Cobalt (ˈkoʊbɒlt is a hard lustrous silver-grey Metal, a Chemical element with symbol Co. Nickel (ˈnɪkəl is a metallic Chemical element with the symbol Ni and Atomic number 28 Copper (ˈkɒpɚ is a Chemical element with the symbol Cu (cuprum and Atomic number 29 Zinc (ˈzɪŋk from Zink is a Metallic Chemical element with the symbol Zn and Atomic number 30 Gallium (ˈgæliəm is a Chemical element that has the symbol Ga and Atomic number 31 Germanium (dʒɚˈmeɪniəm is a Chemical element with the symbol Ge and Atomic number 32 Arsenic (ˈɑrsənɪk is a Chemical element that has the symbol As and Atomic number of 33 Selenium (səˈliniəm is a Chemical element with the Atomic number 34 represented by the chemical symbol Se, an atomic mass of 78 Krypton (ˈkrɪptən or /ˈkrɪptɒn/ from kryptos "hidden" is a Chemical element with the symbol Kr and Atomic number 36 A period 5 element is one of the Chemical elements in the fifth row (or period) of the periodic table of the elements. Rubidium (ruːˈbɪdiəm /rəˈbɪdiəm/ is a Chemical element with the symbol Rb and Atomic number 37 Strontium (ˈstrɒntiəm /ˈstrɒnʃiəm/) is a Chemical element with the symbol Sr and the Atomic number 38 Yttrium (ˈɪtriəm is a Chemical element with symbol Y and Atomic number 39 Zirconium (zɚˈkoʊniəm /ˌzɝˈkoʊniəm/ is a Chemical element with the symbol Zr and Atomic number 40 Niobium (naɪˈoʊbiəm or columbium (/kəˈlʌmbiəm/ is a Chemical element that has the symbol Nb and Atomic number 41 Molybdenum (məˈlɪbdənəm from the Greek word for the metal " Lead " is a Group 6 Chemical element with the symbol Mo Technetium (tɛkˈniːʃɪəm is the lightest Chemical element with no Stable isotope. Ruthenium (ruːˈθiːniəm is a Chemical element that has the symbol Ru and Atomic number 44 Rh redirects here For other uses see Rh (disambiguation Rhodium (ˈroʊdiəm is a Chemical element with the symbol Palladium (pronounced \pəˈleɪdiəm\ is a rare and lustrous silvery-white metal that was discovered in 1803 by William Hyde Wollaston, who named it palladium after the Silver (ˈsɪlvɚ is a Chemical element with the symbol " Ag " (argentum from the Ancient Greek: ἀργήντος - argēntos gen Cadmium (ˈkædmiəm is a Chemical element with the symbol Cd and Atomic number 48 Indium (ˈɪndiəm is a Chemical element with chemical symbol In and Atomic number 49 Tin is a Chemical element with the symbol Sn (stannum and Atomic number 50 Antimony (IPA (Received Pronunciation, /ˈæntɪmoʊni/ (US is a Chemical element with the symbol Sb (stibium meaning "mark" and Tellurium (tɪˈlʊəriəm/ /tɛl- is a Chemical element that has the symbol Te and Atomic number 52 Iodine (ˈaɪədaɪn ˈaɪədɪn or /ˈaɪədiːn/ from ιώδης iodes "violet" is a Chemical element that has the symbol I and Atomic Xenon (ˈzɛnɒn or) is a Chemical element represented by the symbol Xe. 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 Caesium or cesium (ˈsiːziəm is the Chemical element with the symbol Cs and Atomic number 55 Barium (ˈbɛəriəm is a Chemical element. It has the symbol Ba, and Atomic number 56 Terminology The Trivial name " Rare earths " is sometimes used to describe all the lanthanoids together with Scandium and Yttrium Hafnium (ˈhæfniəm is a Chemical element that has the symbol Hf and Atomic number 72 Tantalum (ˈtæntələm (formerly tantalium /tænˈtæliəm/ is a Chemical element with the symbol Ta and Atomic number 73 Tungsten (ˈtʌŋstən also known as wolfram (/ˈwʊlfrəm/ is a Chemical element that has the symbol W and Atomic number 74 Rhenium (ˈriːniəm is a Chemical element with the symbol Re and Atomic number 75 Osmium (ˈɒzmiəm is a Chemical element that has the symbol Os and Atomic number 76 Iridium (ɪˈrɪdiəm is a Chemical element that has the symbol Ir and Atomic number 77 Platinum (ˈplætɪnəm is a Chemical element with the Atomic symbol Pt and an Atomic number of 78 Gold (ˈɡoʊld is a Chemical element with the symbol Au (from its Latin name aurum) and Atomic number 79 Mercury (ˈmɜrkjʊri also called quicksilver or hydrargyrum, is a Chemical element with the symbol Hg ( Latinized hydrargyrum Thallium (ˈθæliəm is a Chemical element with the symbol Tl and Atomic number 81 Characteristics Lead has a dull luster and is a dense, Ductile, very soft highly Bismuth (ˈbɪzməθ is a Chemical element that has the symbol Bi and Atomic number 83 Polonium (pəˈloʊniəm is a Chemical element with the symbol Po and Atomic number 84 discovered in 1898 by Marie and Pierre Curie Astatine (ˈæstətiːn is a Radioactive Chemical element with the symbol At and Atomic number 85 Radon (ˈreɪdɒn is the Chemical element that has the symbol Rn and Atomic number 86 A period 7 element is one of the Chemical elements in the seventh row (or period) of the periodic table of the elements. Francium (ˈfrænsiəm formerly known as eka-caesium and actinium K, is a Chemical element that has the symbol Fr and Radium (ˈreɪdiəm is a radioactive Chemical element which has the symbol Ra and Atomic number 88 History of the actinoid series From the earlier known chemical properties of actinium (89 up to uranium (92 indicating a relation to the Transition metals it was generally Rutherfordium (ˌrʌðɚˈfɔrdiəm is a Chemical element in the Periodic table that has the symbol Rf and Atomic number 104 Dubnium (ˈduːbniəm is a Chemical element in the Periodic table that has the symbol Db and Atomic number 105 Seaborgium (siːˈbɔrgiəm is a Chemical element in the Periodic table that has the symbol Sg and Atomic number 106 Image of Seaborgium Bohrium (ˈbɔəriəm is a Chemical element in the Periodic table that has the symbol Bh and Atomic number 107 Hassium (ˈhæsiəm or /ˈhɑːsiəm/ is a Synthetic element in the Periodic table that has the symbol Hs and Atomic number 108 Meitnerium (maɪtˈnɜriəm is a Chemical element in the Periodic table that has the symbol Mt and Atomic number 109 Darmstadtium (dɑrmˈʃtætiəm formerly known as Ununnilium is a Chemical element with the symbol Ds and Atomic number 110 Roentgenium (rɛntˈgɛniəm /rʌntˈdʒɛniəm/ is a Chemical element in the Periodic table that has the symbol Rg and Atomic number Ununtrium (juːˈnʌntriəm or /əˈnʌntriəm/ is the temporary name of a Synthetic element in the Periodic table that has the temporary symbol Uut and Ununquadium (ˌjuːnənˈkwɒdiəm or /ˌʌnənˈkwɒdiəm/ is the temporary name of a radioactive Chemical element in the Periodic table that has the Ununpentium (ˌjuːnənˈpɛntiəm or /ˌʌnənˈpɛntiəm/ is the temporary name of a synthetic Superheavy element in the Periodic table that has the Ununhexium (ˌjuːnənˈhɛksiəm or /ˌʌnənˈhɛksiəm/ is the temporary name of a synthetic Superheavy element in the Periodic table that has the temporary Ununseptium (ˌjuːnənˈsɛptiəm or /ˌʌnənˈsɛptiəm/ is the temporary name of an undiscovered Chemical element in the Periodic table that has the temporary Ununoctium (ˌjuːnəˈnɒktiəm or /ˌʌnəˈnɒktiəm/ also known as eka-radon or element 118, is the temporary IUPAC name for Terminology The Trivial name " Rare earths " is sometimes used to describe all the lanthanoids together with Scandium and Yttrium Lanthanum (ˈlænθənəm is a Chemical element with the symbol La and Atomic number 57 Cerium (ˈsɪəriəm is a Chemical element with the symbol Ce and Atomic number 58 Praseodymium (ˌpreɪzioʊˈdɪmiəm or /ˌpreɪsioʊˈdɪmiəm/ is a Chemical element that has the symbol Pr and Atomic number 59 Neodymium (ˌniːoʊˈdɪmiəm is a Chemical element with the symbol Nd and Atomic number 60 Promethium (prəˈmiːθiəm/ /proʊˈmiːθiəm is a Chemical element with the symbol Pm and Atomic number 61 Samarium (səˈmɛəriəm is a Chemical element with the symbol Sm and Atomic number 62 Europium (jʊˈroʊpiəm is a Chemical element with the symbol Eu and Atomic number 63 Gadolinium (ˌgædəˈlɪniəm is a Chemical element that has the symbol Gd and Atomic number 64 Terbium (ˈtɝbiəm is a Chemical element with the symbol Tb and Atomic number 65 Holmium (ˈhoʊlmiəm is a Chemical element with the symbol Ho and Atomic number 67 Erbium (ˈɝbiəm is a Chemical element with the symbol Er and Atomic number 68 Thulium (ˈθjuːliəm is a Chemical element that has the symbol Tm and Atomic number 69 Lutetium (ljuːˈtiːʃiəm is a Chemical element with the symbol Lu and Atomic number 71 History of the actinoid series From the earlier known chemical properties of actinium (89 up to uranium (92 indicating a relation to the Transition metals it was generally Actinium (ækˈtɪniəm is a radioactive Chemical element with the symbol Ac and Atomic number 89 which was discovered in 1899, the earliest Thorium (ˈθɔːriəm is a Chemical element with the symbol Th and Atomic number 90 Protactinium (ˌproʊtækˈtɪniəm is a Chemical element with the symbol Pa and Atomic number 91 Uranium (jʊˈreɪniəm is a silvery-gray Metallic Chemical element in the Neptunium (nɛpˈtjuːniəm is a Chemical element with the symbol Np and Atomic number 93 Americium (ˌæməˈrɪsiəm is a Synthetic element that has the symbol Am and Atomic number 95 This article is about the chemical element Curium for the ancient city also called Curium (located in Cyprus see Kourion Curium (ˈkjuːriəm Bk redirects here For other uses of the abbreviation see BK (disambiguation. Californium (ˌkælɪˈforniəm is a Metallic Chemical element with the symbol Cf and Atomic number 98 Einsteinium (aɪnˈstaɪniəm is a Metallic Synthetic element. Fermium (ˈfɝmiəm is a Synthetic element with the symbol Fm and Atomic number 100 Mendelevium (ˌmɛndəˈlɛviəm is a Synthetic element with the symbol Md (formerly Mv) and the Atomic number 101 Nobelium (noʊˈbɛliəm or /noʊˈbiːliəm/ is a Synthetic element with the symbol No and Atomic number 102 Lawrencium (ləˈrɛnsiəm is a Radioactive Synthetic element with the symbol Lr (formerly Lw) and Atomic number 103 In Chemistry a group, also known as a family, is a vertical column in the Periodic table of the Chemical elements There are 18 groups in 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 Trends The alkali metals show a number of trends when moving down the group - for instance decreasing electronegativity increasing reactivity and decreasing melting and boiling Biological occurrences Beryllium's low aqueous solubility means it is rarely available to biological systems it has no known role in living organisms and when encountered Terminology The Trivial name " Rare earths " is sometimes used to describe all the lanthanoids together with Scandium and Yttrium History of the actinoid series From the earlier known chemical properties of actinium (89 up to uranium (92 indicating a relation to the Transition metals it was generally In Chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings It commonly refers to any element in Metalloid is a term used in Chemistry when classifying the Chemical elements On the basis of their general physical and chemical properties nearly every element Nonmetal is a term used in Chemistry when classifying the Chemical elements On the basis of their general physical and chemical properties every element in the Abundance Owing to their high Reactivity, the halogens are found in the environment only in compounds or as Ions Halide ions and oxoanions History Noble gas is translated from the German noun de ''Edelgas'' first used in 1898 by Hugo Erdmann to indicate their extremely low level of reactivity In Chemistry, periodic trends are the tendencies of certain elemental characteristics to increase or decrease as one progresses from one corner of the Periodic table This is caused by the filling of the valence shell of the atom; a group 7A atom releases more energy than a group 1A atom on gaining an electron because it obtains a filled valence shell.

A trend of decreasing Eea going down the groups in the periodic table would be expected. The additional electron will be entering an orbital farther away from the nucleus, and thus would experience a lesser effective nuclear charge. However, a clear counterexample to this trend can be found in group 2A, and this trend only applies to group 1A atoms.

Molecular electron affinities

Eea is not limited to the elements but also applies to molecules. For instance the electron affinity for benzene is negative, as is that of naphthalene, while those of anthracene,phenanthrene and pyrene are positive. Benzene, or benzol, is an organic Chemical compound and a known Carcinogen with the molecular formula C 6 H 6 Naphthalene, also known as naphthalin, naphthaline, tar camphor, white tar, albocarbon, or antimite and not to be Anthracene is a solid Polycyclic aromatic hydrocarbon consisting of three fused Benzene rings derived from Coal-tar. Phenanthrene is a Polycyclic aromatic hydrocarbon composed of three fused Benzene rings Pyrene is a Polycyclic aromatic hydrocarbon (PAH consisting of four fused Benzene rings resulting in a large flat Aromatic system In silico experiments show that the electron affinity of hexacyanobenzene surpasses that of fullerene [1]. In Silico is the second full-length studio album by Australian Drum and bass band Pendulum, released in Australia and "C60" and "C-60" redirect here For other uses see C60 (disambiguation.

See also

References

  1. ^ Remarkable electron accepting properties of the simplest benzenoid cyanocarbons: hexacyanobenzene, octacyanonaphthalene and decacyanoanthracene Xiuhui Zhang, Qianshu Li, Justin B. Koopmans' theorem is an approximation in Molecular orbital theory, such as Density functional theory, or Hartree-Fock theory in which the first Ionization A one-electron reduction in Organic chemistry involves the transfer of an electron from a Metal to an organic substrate. The ionization potential, ionization energy or EI of an Atom or Molecule is the Energy required to remove an Electron " Electronegativity " is the opposite of " Electropositivity," which describes an element's ability to donate electrons In chemistry valence electrons are the Electrons contained in the outermost or valence, Electron shell of an Atom. Ingels, Andrew C. Simmonett, Steven E. Wheeler, Yaoming Xie, R. Bruce King, Henry F. Schaefer III and F. Albert Cotton Chemical Communications, 2006, 758 - 760 Abstract

External links

The International Union of Pure and Applied Chemistry ( IUPAC) (aɪjuːpæk or ay-yoo-pec) is an international Non-governmental organization Compendium of Chemical Terminology (ISBN 0-86542-684-8 is a book published by IUPAC containing internationally accepted definitions for terms in Chemistry.
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