Nmero atmicoNombreSmboloPeriodo,Grupopeso atmico(uma)Densidad(g/cm)a20CPunto de fusin(C)Punto de ebullicin(C)Ao de sudescubrimientoDescubridor
1HidrgenoH1, 11.00794(7) 0.084 g/l-259.1-252.691766T. Von Hohenheim (Paracelso)
2HelioHe1, 184.002602(2) 0.17 g/l-272.2-268.91895RamsayyCleve
3LitioLi2, 16.941(2 0.53180.513171817Arfwedson
4BerilioBe2, 29.012182(3)1.85127829701797Vauquelin
5BoroB2, 1310.811(7) 2.46230025501808DavyyGay-Lussac
6CarbonoC2, 1412.0107(8) 3.5135504827PrehistoriaDesconocido
7NitrgenoN2, 1514.0067(2) 1.17 g/l-209.9-195.81772Rutherford
8OxgenoO2, 1615.9994(3) 1.33 g/l-218.4-182.91774PriestlyyScheele
9FlorF2, 1718.9984032(5)1.58 g/l-219.6-188.11886Moissan
10NenNe2, 1820.1797(6) 0.84 g/l-248.7-246.11898RamsayyTravers
11SodioNa3, 122.98976928(2)0.9797.88921807Davy
12MagnesioMg3, 224.3050(6)1.74648.811071755Black
13AluminioAl3, 1326.9815386(8)2.70660.524671825Oersted
14SilicioSi3, 1428.0855(3) 2.33141023551824Berzelius
15FsforoP3, 1530.973762(2)1.8244 (P4)280(P4)1669Brand
16AzufreS3, 1632.065(5) 2.06113444.7PrehistoriaDesconocido
17CloroCl3, 1735.453(2) 2.95 g/l-34.6-1011774Scheele
18ArgnAr3, 1839.948(1) 1.66 g/l-189.4-185.91894RamsayyRayleigh
19PotasioK4, 139.0983(1)0.8663.77741807Davy
20CalcioCa4, 240.078(4) 1.5483914871808Davy
21EscandioSc4, 344.955912(6)2.99153928321879Nilson
22TitanioTi4, 447.867(1)4.51166032601791GregoryKlaproth
23VanadioV4, 550.9415(1)6.09189033801801del Ro
24CromoCr4, 651.9961(6)7.14185724821797Vauquelin
25ManganesoMn4, 754.938045(5)7.44124420971774Gahn
26HierroFe4, 855.845(2)7.8715352750PrehistoriaDesconocido
27CobaltoCo4, 958.933195(5)8.89149528701735Brandt
28NquelNi4, 1058.6934(2)8.91145327321751Cronstedt
29CobreCu4, 1163.546(3) 8.921083.52595PrehistoriaDesconocido
30ZincZn4, 1265.409(4)7.14419.6907PrehistoriaParacelso
31GalioGa4, 1369.723(1)5.9129.824031875Lecoq de Boisbaudran
32GermanioGe4, 1472.64(1)5.32937.428301886Winkler
33ArsnicoAs4, 1574.92160(2)5.72613613(sublimacin)ca. 1250Albertus Magnus
34SelenioSe4, 1678.96(3) 4.822176851817Berzelius
35BromoBr4, 1779.904(1)3.14-7.358.81826Balard
36KriptnKr4, 1883.798(2) 3.48 g/l-156.6-152.31898RamsayyTravers
37RubidioRb5, 185.4678(3) 1.53396881861BunsenyKirchhoff
38EstroncioSr5, 287.62(1) 2.6376913841790Crawford
39ItrioY5, 388.90585(2)4.47152333371794Gadolin
40CirconioZr5, 491.224(2) 6.51185243771789Klaproth
41NiobioNb5, 592.906 38(2)8.58246849271801Hatchett
42MolibdenoMo5, 695.94(2) 10.28261755601778Scheele
43TecnecioTc5, 7[98.9063] 11.49217250301937PerrierySegr
44RutenioRu5, 8101.07(2) 12.45231039001844Klaus
45RodioRh5, 9102.90550(2)12.41196637271803Wollaston
46PaladioPd5, 10106.42(1) 12.02155231401803Wollaston
47PlataAg5, 11107.8682(2) 10.49961.92212PrehistoriaDesconocido
48CadmioCd5, 12112.411(8) 8.643217651817StrohmeyeryHermann
49IndioIn5, 13114.818(3)7.31156.220801863ReichyRichter
50EstaoSn5, 14118.710(7) 7.292322270PrehistoriaDesconocido
51AntimonioSb5, 15121.760(1) 6.69630.71750PrehistoriaDesconocido
52TeluroTe5, 16127.60(3) 6.25449.69901782von Reichenstein
53YodoI5, 17126.90447(3)4.94113.5184.41811Courtois
54XennXe5, 18131.293(6) 4.49 g/l-111.9-1071898RamsayyTravers
55CesioCs6, 1132.9054519(2)1.9028.46901860KirchhoffyBunsen
56BarioBa6, 2137.327(7)3.6572516401808Davy
57LantanoLa6138.90547(7) 6.1692034541839Mosander
58CerioCe6140.116(1) 6.7779832571803W. HisingeryBerzelius
59PraseodimioPr6140.90765(2)6.4893132121895von Welsbach
60NeodimioNd6144.242(3) 7.00101031271895von Welsbach
61PrometioPm6[146.9151] 7.22108027301945MarinskyyGlendenin
62SamarioSm6150.36(2) 7.54107217781879Lecoq de Boisbaudran
63EuropioEu6151.964(1) 5.2582215971901Demaray
64GadolinioGd6157.25(3) 7.89131132331880de Marignac
65TerbioTb6158.92535(2)8.25136030411843Mosander
66DisprosioDy6162.500(1) 8.56140923351886Lecoq de Boisbaudran
67HolmioHo6164.93032(2)8.78147027201878Soret
68ErbioEr6167.259(3) 9.05152225101842Mosander
69TulioTm6168.93421(2)9.32154517271879Cleve
70IterbioYb6173.04(3) 6.9782411931878de Marignac
71LutecioLu6, 3174.967(1) 9.84165633151907Urbain
72HafnioHf6, 4178.49(2)13.31215054001923Costeryde Hevesy
73TantalioTa6, 5180.9479(1)16.68299654251802Ekeberg
74WolframioW6, 6183.84(1)19.26340759271783Elhuyar
75RenioRe6, 7186.207(1)21.03318056271925Noddack,TackeyBerg
76OsmioOs6, 8190.23(3) 22.61304550271803Tennant
77IridioIr6, 9192.217(3)22.65241041301803Tennant
78PlatinoPt6, 10195.084(9)21.45177238271557de Ulloa
79OroAu6, 11196.966569(4)19.321064.42940PrehistoriaDesconocido
80MercurioHg6, 12200.59(2)13.55-38.9356.6PrehistoriaDesconocido
81TalioTl6, 13204.3833(2)11.85303.614571861Crookes
82PlomoPb6, 14207.2(1)11.34327.51740PrehistoriaDesconocido
83BismutoBi6, 15208.98040(1)9.80271.415601540Geoffroy
84PolonioPo6, 16[208.9824] 9.202549621898MarieyPierre Curie
85AstatoAt6, 17[209.9871] 3023371940CorsonyMacKenzie
86RadnRn6, 18[222.0176] 9.23 g/l-71-61.81900Dorn
87FrancioFr7, 1[223.0197] 276771939Perey
88RadioRa7, 2[226.0254] 5.5070011401898MarieyPierre Curie
89ActinioAc7[227.0278] 10.07104731971899Debierne
90TorioTh7232.03806(2) 11.72175047871829Berzelius
91ProtactinioPa7231.03588(2) 15.37155440301917Soddy,CranstonyHahn
92UranioU7238.02891(318.971132.438181789Klaproth
93NeptunioNp7[237.0482] 20.4864039021940McMillanyAbelson
94PlutonioPu7[244.0642] 19.7464133271940Seaborg
95AmericioAm7[243.0614] 13.6799426071944Seaborg
96CurioCm7[247.0703] 13.5113401944Seaborg
97BerkelioBk7[247.0703] 13.259861949Seaborg
98CalifornioCf7[251.0796] 15.19001950Seaborg
99EinstenioEs7[252.0829] 8601952Seaborg
100FermioFm7[257.0951] 1952Seaborg
101MendelevioMd7[258.0986] 1955Seaborg
102NobelioNo7[259.1009] 1958Seaborg
103LaurencioLr7, 3[260.1053] 1961Ghiorso
104RutherfordioRf7, 4[261.1087] 1964/69Flerov
105DubnioDb7, 5[262.1138] 1967/70Flerov
106SeaborgioSg7, 6[263.1182] 1974Flerov
107BohrioBh7, 7[262.1229] 1976Oganessian
108HassioHs7, 8[265] 1984GSI(*)
109MeitnerioMt7, 9[266] 1982GSI
110DarmstadtioDs7, 10[269] 1994GSI
111RoentgenioRg7, 11[272] 1994GSI
112CopernicioCn7, 12[285] 1996GSI
113UnuntrioUut7, 13[284] 2004JINR(*),LLNL(*)
114FlerovioFl7, 14[289] 1999JINR
115UnunpentioUup7, 15[288] 2004JINR,LLNL
116LivermorioLv7, 16[290] 2006JINR,LLNL(**)
117UnunseptioUus7, 172009-2010JINR
118UnunoctioUuo7, 18[294]52006JINR,LLNL(**)