List of chemical elements

Last updated

As of February 2024, 118 chemical elements have been identified and named officially by IUPAC. A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number, or Z). [1]

Contents

The definitive visualisation of all 118 elements is the periodic table of the elements, whose history along the principles of the periodic law was one of the founding developments of modern chemistry. It is a tabular arrangement of the elements by their chemical properties that usually uses abbreviated chemical symbols in place of full element names, but the linear list format presented here is also useful. Like the periodic table, the list below organizes the elements by the number of protons in their atoms; it can also be organized by other properties, such as atomic weight, density, and electronegativity. For more detailed information about the origins of element names, see List of chemical element name etymologies.

List

Element Origin of name [2] [3] Group Period Block Standard
atomic
weight
Ar°(E) [lower-alpha 1]
Density [lower-alpha 2] [lower-alpha 3] Melting point [lower-alpha 4] Boiling point [lower-alpha 5] Specific
heat
capacity
[lower-alpha 6]
Electro­negativity [lower-alpha 7] Abundance
in Earth's
crust
[lower-alpha 8]
Origin [lower-alpha 9] Phase at r.t. [lower-alpha 10]
Atomic number
Z
Symbol Name(Da)(g/cm3)(K)(K)(J/g ·K)(mg/kg)
 
1H Hydrogen Greek elements hydro- and -gen, 'water-forming'11 s-block 1.00800.0000898814.0120.2814.3042.201400 primordial gas
2He Helium Greek hḗlios, 'sun'181s-block4.00260.0001785 [lower-alpha 11] 4.225.1930.008primordialgas
3Li Lithium Greek líthos, 'stone'12s-block6.940.534453.6915603.5820.9820primordial solid
4Be Beryllium Beryl, a mineral (ultimately from the name of Belur in southern India) [4] 22s-block9.01221.85156027421.8251.572.8primordialsolid
5B Boron Borax, a mineral (from Arabic bawraq , Middle Persian *bōrag)132 p-block 10.812.34234942001.0262.0410primordialsolid
6C Carbon Latin carbo, 'coal'142p-block12.0112.267>400043000.7092.55200primordialsolid
7N Nitrogen Greek nítron and -gen, 'niter-forming'152p-block14.0070.001250663.1577.361.043.0419primordialgas
8O Oxygen Greek oxy- and -gen, 'acid-forming'162p-block15.9990.00142954.3690.200.9183.44461000primordialgas
9F Fluorine Latin fluere, 'to flow'172p-block18.9980.00169653.5385.030.8243.98585primordialgas
10Ne Neon Greek néon, 'new'182p-block20.1800.000900224.5627.071.030.005primordialgas
11Na Sodium Coined by Humphry Davy who first isolated it, from English soda (specifically caustic soda), via Italian from Arabic ṣudāʕ 'headache'
 · Symbol Na is derived from Neo-Latin natrium , coined from German Natron , 'natron'
13s-block22.9900.968370.8711561.2280.9323600primordialsolid
12Mg Magnesium Magnesia, a district of Eastern Thessaly in Greece 23s-block24.3051.73892313631.0231.3123300primordialsolid
13Al Aluminium Alumina, from Latin alumen (gen. aluminis), 'bitter salt, alum'133p-block26.9822.70933.4727920.8971.6182300primordialsolid
14Si Silicon Latin silex, 'flint' (originally silicium)143p-block28.0852.3290168735380.7051.9282000primordialsolid
15P Phosphorus Greek phōsphóros, 'light-bearing'153p-block30.9741.823317.305500.7692.191050primordialsolid
16S Sulfur Latin163p-block32.062.07388.36717.870.712.58350primordialsolid
17Cl Chlorine Greek chlōrós, 'greenish yellow'173p-block35.450.0032171.6239.110.4793.16145primordialgas
18Ar Argon Greek argós, 'idle' (because of its inertness)183p-block39.950.00178483.8087.300.523.5primordialgas
19K Potassium Neo-Latin potassa, 'potash', itself from pot and ash
 · Symbol K is derived from Neo-Latin kalium , from German
14s-block39.0980.89336.5310320.7570.8220900primordialsolid
20Ca Calcium Latin calx, 'lime'24s-block40.0781.55111517570.6471.0041500primordialsolid
21Sc Scandium Latin Scandia, 'Scandinavia'34 d-block 44.9562.985181431090.5681.3622primordialsolid
22Ti Titanium Titans, the sons of the earth goddess of Greek mythology44d-block47.8674.506194135600.5231.545650primordialsolid
23V Vanadium Vanadis, an Old Norse name for the Scandinavian goddess Freyja 54d-block50.9426.11218336800.4891.63120primordialsolid
24Cr Chromium Greek chróma, 'colour'64d-block51.9967.15218029440.4491.66102primordialsolid
25Mn Manganese Corrupted from magnesia negra ; see § magnesium 74d-block54.9387.21151923340.4791.55950primordialsolid
26Fe Iron English, from Proto-Celtic *īsarnom ('iron'), from a root meaning 'blood'
 · Symbol Fe is derived from Latin ferrum
84d-block55.8457.874181131340.4491.8356300primordialsolid
27Co Cobalt German Kobold , 'goblin'94d-block58.9338.90176832000.4211.8825primordialsolid
28Ni Nickel Nickel, a mischievous sprite of German miner mythology104d-block58.6938.908172831860.4441.9184primordialsolid
29Cu Copper English, from Latin cuprum , from Ancient Greek Kýpros 'Cyprus'114d-block63.5468.961357.7728350.3851.9060primordialsolid
30Zn Zinc Most likely from German Zinke , 'prong' or 'tooth', though some suggest Persian sang , 'stone'124d-block65.387.14692.8811800.3881.6570primordialsolid
31Ga Gallium Latin Gallia , 'France'134p-block69.7235.91302.914626730.3711.8119primordialsolid
32Ge Germanium Latin Germania , 'Germany'144p-block72.6305.3231211.4031060.322.011.5primordialsolid
33As Arsenic Middle English, from Middle French arsenic , from Greek arsenikón 'yellow arsenic' (influenced by arsenikós , 'masculine' or 'virile'), from a West Asian wanderword ultimately from Old Iranian *zarniya-ka, 'golden'154p-block74.9225.7271090 [lower-alpha 12] 8870.3292.181.8primordialsolid
34Se Selenium Greek selḗnē , 'moon'164p-block78.9714.814539580.3212.550.05primordialsolid
35Br Bromine Greek brômos , 'stench'174p-block79.9043.1028265.8332.00.4742.962.4primordial liquid
36Kr Krypton Greek kryptós , 'hidden'184p-block83.7980.003749115.79119.930.2483.001×10−4primordialgas
37Rb Rubidium Latin rubidus , 'deep red'15s-block85.4681.532312.469610.3630.8290primordialsolid
38Sr Strontium Strontian, a village in Scotland, where it was found25s-block87.622.64105016550.3010.95370primordialsolid
39Y Yttrium Ytterby, Sweden, where it was found; see also terbium, erbium, ytterbium 35d-block88.9064.472179936090.2981.2233primordialsolid
40Zr Zirconium Zircon, a mineral, from Persian zargun, 'gold-hued'45d-block91.2246.52212846820.2781.33165primordialsolid
41Nb Niobium Niobe, daughter of king Tantalus from Greek mythology; see also tantalum 55d-block92.9068.57275050170.2651.620primordialsolid
42Mo Molybdenum Greek molýbdaina , 'piece of lead', from mólybdos , 'lead', due to confusion with lead ore galena (PbS)65d-block95.9510.28289649120.2512.161.2primordialsolid
43Tc Technetium Greek tekhnētós , 'artificial'75d-block[97] [lower-alpha 1] 11243045381.9~ 3×10−9 from decay solid
44Ru Ruthenium Neo-Latin Ruthenia , 'Russia'85d-block101.0712.45260744230.2382.20.001primordialsolid
45Rh Rhodium Greek rhodóeis , 'rose-coloured', from rhódon , 'rose'95d-block102.9112.41223739680.2432.280.001primordialsolid
46Pd Palladium Pallas, an asteroid, considered a planet at the time105d-block106.4212.0231828.0532360.2442.200.015primordialsolid
47Ag Silver English, from a common Germanic root
 · Symbol Ag is derived from Latin argentum
115d-block107.8710.491234.9324350.2351.930.075primordialsolid
48Cd Cadmium Neo-Latin cadmia , 'calamine', from King Kadmos, legendary founder of Thebes125d-block112.418.65594.2210400.2321.690.159primordialsolid
49In Indium Latin indicum , 'indigo', the blue colour found in its spectrum135p-block114.827.31429.7523450.2331.780.25primordialsolid
50Sn Tin English, from a common Germanic root
 · Symbol Sn is derived from Latin stannum
145p-block118.717.265505.0828750.2281.962.3primordialsolid
51Sb Antimony Latin antimonium , the origin of which is uncertain: folk etymologies suggest it is derived from Greek antí ('against') + mónos ('alone'), or Old French anti-moine , 'Monk's bane', but it could plausibly be from or related to Arabic ʾiṯmid , 'antimony', reformatted as a Latin word
 · Symbol Sb is derived from Latin stibium 'stibnite'
155p-block121.766.697903.7818600.2072.050.2primordialsolid
52Te Tellurium Latin tellus , 'the ground, earth'165p-block127.606.24722.6612610.2022.10.001primordialsolid
53I Iodine French iode , from Greek ioeidḗs , 'violet'175p-block126.904.933386.85457.40.2142.660.45primordialsolid
54Xe Xenon Greek xénon , neuter form of xénos 'strange, foreign'185p-block131.290.005894161.4165.030.1582.603×10−5primordialgas
55Cs Caesium Latin caesius , 'sky-blue'16s-block132.911.93301.599440.2420.793primordialsolid
56Ba Barium Greek barýs , 'heavy'26s-block137.333.51100021700.2040.89425primordialsolid
57La Lanthanum Greek lanthánein , 'to lie hidden'f-block groups6 f-block 138.916.162119337370.1951.139primordialsolid
58Ce Cerium Ceres, a dwarf planet, considered a planet at the timef-block groups6f-block140.126.770106837160.1921.1266.5primordialsolid
59Pr Praseodymium Greek prásios dídymos , 'green twin'f-block groups6f-block140.916.77120837930.1931.139.2primordialsolid
60Nd Neodymium Greek néos dídymos , 'new twin'f-block groups6f-block144.247.01129733470.191.1441.5primordialsolid
61Pm Promethium Prometheus, a figure in Greek mythologyf-block groups6f-block[145]7.26131532731.132×10−19from decaysolid
62Sm Samarium Samarskite, a mineral named after V. Samarsky-Bykhovets, Russian mine officialf-block groups6f-block150.367.52134520670.1971.177.05primordialsolid
63Eu Europium Europe f-block groups6f-block151.965.244109918020.1821.22primordialsolid
64Gd Gadolinium Gadolinite, a mineral named after Johan Gadolin, Finnish chemist, physicist and mineralogistf-block groups6f-block157.257.90158535460.2361.26.2primordialsolid
65Tb Terbium Ytterby, Sweden, where it was found; see also yttrium, erbium, ytterbium f-block groups6f-block158.938.23162935030.1821.21.2primordialsolid
66Dy Dysprosium Greek dysprósitos , 'hard to get'f-block groups6f-block162.508.540168028400.171.225.2primordialsolid
67Ho Holmium Neo-Latin Holmia, 'Stockholm'f-block groups6f-block164.938.79173429930.1651.231.3primordialsolid
68Er Erbium Ytterby, Sweden, where it was found; see also yttrium, terbium, ytterbium f-block groups6f-block167.269.066180231410.1681.243.5primordialsolid
69Tm Thulium Thule, the ancient name for an unclear northern locationf-block groups6f-block168.939.32181822230.161.250.52primordialsolid
70Yb Ytterbium Ytterby, Sweden, where it was found; see also yttrium, terbium, erbium f-block groups6f-block173.056.90109714690.1551.13.2primordialsolid
71Lu Lutetium Latin Lutetia', 'Paris'36d-block174.979.841192536750.1541.270.8primordialsolid
72Hf Hafnium Neo-Latin Hafnia, 'Copenhagen' (from Danish havn , harbour)46d-block178.4913.31250648760.1441.33primordialsolid
73Ta Tantalum King Tantalus, father of Niobe from Greek mythology; see also niobium 56d-block180.9516.69329057310.141.52primordialsolid
74W Tungsten Swedish tung sten , 'heavy stone'
 · Symbol W is from Wolfram, originally from Middle High German wolf-rahm 'wolf's foam' describing the mineral wolframite [5]
66d-block183.8419.25369558280.1322.361.3primordialsolid
75Re Rhenium Latin Rhenus , 'Rhine'76d-block186.2121.02345958690.1371.97×10−4primordialsolid
76Os Osmium Greek osmḗ , 'smell'86d-block190.2322.59330652850.132.20.002primordialsolid
77Ir Iridium Iris, the Greek goddess of the rainbow96d-block192.2222.56271947010.1312.200.001primordialsolid
78Pt Platinum Spanish platina , 'little silver', from plata 'silver'106d-block195.0821.452041.440980.1332.280.005primordialsolid
79Au Gold English, from the same Proto-Indo-European root as 'yellow'
 · Symbol Au is derived from Latin aurum
116d-block196.9719.31337.3331290.1292.540.004primordialsolid
80Hg Mercury Mercury, Roman god of commerce, communication, and luck, known for his speed and mobility
 · Symbol Hg is derived from its Latin name hydrargyrum , from Greek hydrárgyros , 'water-silver'
126d-block200.5913.534234.43629.880.142.000.085primordialliquid
81Tl Thallium Greek thallós , 'green shoot or twig'136p-block204.3811.8557717460.1291.620.85primordialsolid
82Pb Lead English, from Proto-Celtic *ɸloudom, from a root meaning 'flow'
 · Symbol Pb is derived from Latin plumbum
146p-block207.211.34600.6120220.1291.87(2+)
2.33 (4+)
14primordialsolid
83Bi Bismuth German Wismut , via Latin and Arabic from Greek psimúthion , 'white lead'156p-block208.989.78544.718370.1222.020.009primordialsolid
84Po Polonium Latin Polonia , 'Poland', home country of Marie Curie, who discovered it166p-block[209] [lower-alpha 1] 9.19652712352.02×10−10from decaysolid
85At Astatine Greek ástatos , 'unstable', alluding to its lack of stable isotopes176p-block[210](8.91–8.95)5756102.23×10−20from decay unknown phase
86Rn Radon Radium emanation, originally the name of the isotope radon-222 186p-block[222]0.00973202211.30.0942.24×10−13from decaygas
87Fr Francium France, home country of discoverer Marguerite Perey 17s-block[223](2.48)281890>0.79 [6] ~ 1×10−18from decayunknown phase
88Ra Radium Coined in French by discoverer Marie Curie, from Latin radius , 'ray'27s-block[226]5.597320100.0940.99×10−7from decaysolid
89Ac Actinium Greek aktís , 'ray'f-block groups7f-block[227]10132334710.121.15.5×10−10from decaysolid
90Th Thorium Thor, the Scandinavian god of thunderf-block groups7f-block232.0411.7211550610.1131.39.6primordialsolid
91Pa Protactinium English prefix proto- (from Greek prôtos , 'first, before') + actinium, since actinium is produced through the radioactive decay of protactiniumf-block groups7f-block231.0415.37184143001.51.4×10−6from decaysolid
92U Uranium Uranus, the seventh planet in the Solar Systemf-block groups7f-block238.0319.11405.344040.1161.382.7primordialsolid
93Np Neptunium Neptune, the eighth planet in the Solar Systemf-block groups7f-block[237]20.4591742731.36 3×10−12from decaysolid
94Pu Plutonium Pluto, a dwarf planet in the Solar System, considered a planet at the timef-block groups7f-block[244]19.85912.535011.28 3×10−11from decaysolid
95Am Americium The Americas, where the element was first synthesised, by analogy with its homologue § europium f-block groups7f-block[243]12144928801.13 synthetic solid
96Cm Curium Pierre Curie and Marie Curie, French physicists and chemistsf-block groups7f-block[247]13.51161333831.28syntheticsolid
97Bk Berkelium Berkeley, California, where the element was first synthesisedf-block groups7f-block[247]14.78125929001.3syntheticsolid
98Cf Californium California, where the element was first synthesised in the LBNL laboratoryf-block groups7f-block[251]15.11173(1743) [lower-alpha 2] 1.3syntheticsolid
99Es Einsteinium Albert Einstein, German physicistf-block groups7f-block[252]8.841133(1269)1.3syntheticsolid
100Fm Fermium Enrico Fermi, Italian physicistf-block groups7f-block[257](9.7) [lower-alpha 2] (1125) [7]
(1800) [8]
1.3syntheticunknown phase
101Md Mendelevium Dmitri Mendeleev, Russian chemist who proposed the periodic table f-block groups7f-block[258](10.3)(1100)1.3syntheticunknown phase
102No Nobelium Alfred Nobel, Swedish chemist and engineerf-block groups7f-block[259](9.9)(1100)1.3syntheticunknown phase
103Lr Lawrencium Ernest Lawrence, American physicist37d-block[266](14.4)(1900)1.3syntheticunknown phase
104Rf Rutherfordium Ernest Rutherford, chemist and physicist from New Zealand47d-block[267](17)(2400)(5800)syntheticunknown phase
105Db Dubnium Dubna, Russia, where the element was discovered in the JINR laboratory57d-block[268](21.6)syntheticunknown phase
106Sg Seaborgium Glenn T. Seaborg, American chemist67d-block[269](23–24)syntheticunknown phase
107Bh Bohrium Niels Bohr, Danish physicist77d-block[270](26–27)syntheticunknown phase
108Hs Hassium Neo-Latin Hassia, 'Hesse', a state in Germany87d-block[269](27–29)syntheticunknown phase
109Mt Meitnerium Lise Meitner, Austrian physicist97d-block[278](27–28)syntheticunknown phase
110Ds Darmstadtium Darmstadt, Germany, where the element was first synthesised in the GSI laboratories107d-block[281](26–27)syntheticunknown phase
111Rg Roentgenium Wilhelm Conrad Röntgen, German physicist117d-block[282](22–24)syntheticunknown phase
112Cn Copernicium Nicolaus Copernicus, Polish astronomer127d-block[285](14.0)(283±11)(340±10) [lower-alpha 2] syntheticunknown phase
113Nh Nihonium Japanese Nihon , 'Japan', where the element was first synthesised in the Riken laboratories137p-block[286](16)(700)(1400)syntheticunknown phase
114Fl Flerovium Flerov Laboratory of Nuclear Reactions, part of JINR, where the element was synthesised; itself named after Georgy Flyorov, Russian physicist147p-block[289](11.4±0.3)(284±50) [lower-alpha 2] syntheticunknown phase
115Mc Moscovium Moscow, Russia, where the element was first synthesised in the JINR laboratories157p-block[290](13.5)(700)(1400)syntheticunknown phase
116Lv Livermorium Lawrence Livermore National Laboratory in Livermore, California 167p-block[293](12.9)(700)(1100)syntheticunknown phase
117Ts Tennessine Tennessee, United States, where Oak Ridge National Laboratory is located177p-block[294](7.1–7.3)(700)(883)syntheticunknown phase
118Og Oganesson Yuri Oganessian, Russian physicist187p-block[294](7)(325±15)(450±10)syntheticunknown phase
  1. 1 2 3 Standard atomic weight
    • '1.0080': abridged value, uncertainty ignored here
    • '[97]', [ ] notation: massnumber of most stable isotope
  2. 1 2 3 4 5 Values in ( ) brackets are predictions
  3. Density ( sources )
  4. Melting point in kelvin  (K) ( sources )
  5. Boiling point in kelvin  (K) ( sources )
  6. Heat capacity ( sources )
  7. Electronegativity by Pauling ( source )
  8. Abundance of elements in Earth's crust
  9. Primordial (=Earth's origin), from decay, or synthetic
  10. Phase at Standard state (25 °C [77 °F], 100 kPa)
  11. Helium melting point: helium does not solidify at a pressure of 1 bar (0.99 atm). Helium can only solidify at pressures above 25 atmosphere.
  12. Arsenic: element sublimes at one atmosphere of pressure.

See also

Related Research Articles

<span class="mw-page-title-main">Atomic number</span> Number of protons found in the nucleus of an atom

The atomic number or nuclear charge number (symbol Z) of a chemical element is the charge number of an atomic nucleus. For ordinary nuclei composed of protons and neutrons, this is equal to the proton number (np) or the number of protons found in the nucleus of every atom of that element. The atomic number can be used to uniquely identify ordinary chemical elements. In an ordinary uncharged atom, the atomic number is also equal to the number of electrons.

Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during reactions with other substances. Chemistry also addresses the nature of chemical bonds in chemical compounds.

A chemical element is a chemical substance that cannot be broken down into other substances by chemical reactions. The basic particle that constitutes a chemical element is the atom. Chemical elements are identified by the number of protons in the nuclei of their atoms, known as the element's atomic number. For example, oxygen has an atomic number of 8, meaning that each oxygen atom has 8 protons in its nucleus. Two or more atoms of the same element can combine to form molecules, in contrast to chemical compounds or mixtures, which contain atoms of different elements. Atoms can be transformed into different elements in nuclear reactions, which change an atom's atomic number.

Electronegativity, symbolized as χ, is the tendency for an atom of a given chemical element to attract shared electrons when forming a chemical bond. An atom's electronegativity is affected by both its atomic number and the distance at which its valence electrons reside from the charged nucleus. The higher the associated electronegativity, the more an atom or a substituent group attracts electrons. Electronegativity serves as a simple way to quantitatively estimate the bond energy, and the sign and magnitude of a bond's chemical polarity, which characterizes a bond along the continuous scale from covalent to ionic bonding. The loosely defined term electropositivity is the opposite of electronegativity: it characterizes an element's tendency to donate valence electrons.

<span class="mw-page-title-main">Francium</span> Chemical element, symbol Fr and atomic number 87

Francium is a chemical element; it has symbol Fr and atomic number 87. It is extremely radioactive; its most stable isotope, francium-223, has a half-life of only 22 minutes. It is the second-most electropositive element, behind only caesium, and is the second rarest naturally occurring element. Francium's isotopes decay quickly into astatine, radium, and radon. The electronic structure of a francium atom is [Rn] 7s1; thus, the element is classed as an alkali metal.

<span class="mw-page-title-main">Noble gas</span> Group of low-reactive, gaseous chemical elements

The noble gases are the naturally occurring members of group 18 of the periodic table: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). Under standard conditions, these elements are odorless, colorless, monatomic gases with very low chemical reactivity and cryogenic boiling points.

<span class="mw-page-title-main">Periodic table</span> Tabular arrangement of the chemical elements ordered by atomic number

The periodic table, also known as the periodic table of the elements, is an ordered arrangement of the chemical elements into rows ("periods") and columns ("groups"). It is an icon of chemistry and is widely used in physics and other sciences. It is a depiction of the periodic law, which states that when the elements are arranged in order of their atomic numbers an approximate recurrence of their properties is evident. The table is divided into four roughly rectangular areas called blocks. Elements in the same group tend to show similar chemical characteristics.

<span class="mw-page-title-main">Synthetic element</span> Chemical elements that do not occur naturally

A synthetic element is one of 24 known chemical elements that do not occur naturally on Earth: they have been created by human manipulation of fundamental particles in a nuclear reactor, a particle accelerator, or the explosion of an atomic bomb; thus, they are called "synthetic", "artificial", or "man-made". The synthetic elements are those with atomic numbers 95–118, as shown in purple on the accompanying periodic table: these 24 elements were first created between 1944 and 2010. The mechanism for the creation of a synthetic element is to force additional protons into the nucleus of an element with an atomic number lower than 95. All known synthetic elements are unstable, but they decay at widely varying rates: the half-lives of their longest-lived isotopes range from microseconds to millions of years.

<span class="mw-page-title-main">Chemical symbol</span> Abbreviations used in chemistry

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<span class="mw-page-title-main">Nuclide</span> Atomic species

A nuclide is a class of atoms characterized by their number of protons, Z, their number of neutrons, N, and their nuclear energy state.

A period 2 element is one of the chemical elements in the second row of the periodic table of the chemical elements. The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behavior of the elements as their atomic number increases; a new row is started when chemical behavior begins to repeat, creating columns of elements with similar properties.

A period 1 element is one of the chemical elements in the first row of the periodic table of the chemical elements. The periodic table is laid out in rows to illustrate periodic (recurring) trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when chemical behaviour begins to repeat, meaning that analog elements fall into the same vertical columns. The first period contains fewer elements than any other row in the table, with only two: hydrogen and helium. This situation can be explained by modern theories of atomic structure. In a quantum mechanical description of atomic structure, this period corresponds to the filling of the 1s orbital. Period 1 elements obey the duet rule in that they need two electrons to complete their valence shell.

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<span class="mw-page-title-main">Group 8 element</span> Group of chemical elements in the periodic table

Group 8 is a group (column) of chemical elements in the periodic table. It consists of iron (Fe), ruthenium (Ru), osmium (Os) and hassium (Hs). "Group 8" is the modern standard designation for this group, adopted by the IUPAC in 1990. It should not be confused with "group VIIIA" in the CAS system, which is group 18, the noble gases. In the older group naming systems, this group was combined with groups 9 and 10 and called group "VIIIB" in the Chemical Abstracts Service (CAS) "U.S. system", or "VIII" in the old IUPAC (pre-1990) "European system". The elements in this group are all transition metals that lie in the d-block of the periodic table.

<span class="mw-page-title-main">Periodic trends</span> Specific recurring patterns that are present in the modern periodic table

In chemistry, periodic trends are specific patterns that are present in the periodic table that illustrate different aspects of certain elements when grouped by period and/or group. They were discovered by the Russian chemist Dmitri Mendeleev in 1863. Major periodic trends include atomic radius, ionization energy, electron affinity, electronegativity, valency and metallic character. These trends exist because of the similar electron configurations of the elements within their respective groups or periods; they reflect the periodic nature of the elements. These trends give a qualitative assessment of the properties of each element.

This glossary of chemistry terms is a list of terms and definitions relevant to chemistry, including chemical laws, diagrams and formulae, laboratory tools, glassware, and equipment. Chemistry is a physical science concerned with the composition, structure, and properties of matter, as well as the changes it undergoes during chemical reactions; it features an extensive vocabulary and a significant amount of jargon.

There are currently 118 known chemical elements with a wide range of physical and chemical properties. Amongst this diversity, scientists have found it useful to apply names for various sets of elements that have similar properties, to varying degrees. Many of these sets are formally recognized by the standards body IUPAC.

<span class="mw-page-title-main">Isotope</span> Different atoms of the same element

Isotopes are distinct nuclear species of the same chemical element. They have the same atomic number and position in the periodic table, but differ in nucleon numbers due to different numbers of neutrons in their nuclei. While all isotopes of a given element have similar chemical properties, they have different atomic masses and physical properties.

A block of the periodic table is a set of elements unified by the atomic orbitals their valence electrons or vacancies lie in. The term seems to have been first used by Charles Janet. Each block is named after its characteristic orbital: s-block, p-block, d-block, f-block and g-block.

References

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  6. Originally assessed as 0.7 by Pauling but never revised after other elements' electronegativities were updated for precision. Predicted to be higher than that of caesium.
  7. Konings, Rudy J. M.; Beneš, Ondrej. "The Thermodynamic Properties of the 𝑓-Elements and Their Compounds. I. The Lanthanide and Actinide Metals". Journal of Physical and Chemical Reference Data. doi:10.1063/1.3474238.
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