Notes- “Aluminum” and “cesium” are commonly used alternative spellings for “aluminium” and “caesium.”- IUPAC 2001 standard atomic weights (mean relative atomic masses) are listed with uncertainties in the last figure in parentheses [R. D. Loss, Pure Appl. Chem. 75, 1107-1122 (2003)].

These values correspond to current best knowledge of the elements in natural terrestrial sources. For elements that have no stable or long-lived nuclides, the mass number of the nuclide with the longest confirmed half-life is listed between square brackets.

- Elements with atomic numbers 112 and above have been reported but not fully authenticated.

Copyright © 2005 IUPAC, the International Union of Pure and Applied Chemistry. For updates to this table, see http://www.iupac.org/reports/periodic_table/. This version is dated 14 January 2005.

1

Hhydrogen

1.007 94(7)

1 18

3

Lilithium

6.941(2)

4

Beberyllium

9.012 182(3)

11

Nasodium

22.989 770(2)

12

Mgmagnesium

24.3050(6)

19

Kpotassium

39.0983(1)

20

Cacalcium

40.078(4)

37

Rbrubidium

85.4678(3)

38

Srstrontium

87.62(1)

38

Srstrontium

87.62(1)

55

Cscaesium

132.905 45(2)

55

Cscaesium

132.905 45(2)

56

Babarium

137.327(7)

87

Frfrancium

[223]

88

Raradium

[226]

5

Bboron

10.811(7)

13

Alaluminium

26.981 538(2)

31

Gagallium

69.723(1)

49

Inindium

114.818(3)

81

Tlthallium

204.3833(2)

6

Ccarbon

12.0107(8)

14

Sisilicon

28.0855(3)

32

Gegermanium

72.64(1)

50

Sntin

118.710(7)

82

Pblead

207.2(1)

7

Nnitrogen

14.0067(2)

15

Pphosphorus

30.973 761(2)

33

Asarsenic

74.921 60(2)

51

Sbantimony

121.760(1)

83

Bibismuth

208.980 38(2)

8

Ooxygen

15.9994(3)

16

Ssulfur

32.065(5)

34

Seselenium

78.96(3)

52

Tetellurium

127.60(3)

84

Popolonium

[209]

9

Ffluorine

18.998 4032(5)

17

Clchlorine

35.453(2)

35

Brbromine

79.904(1)

53

Iiodine

126.904 47(3)

85

Atastatine

[210]

10

Neneon

20.1797(6)

2

Hehelium

4.002 602(2)

18

Arargon

39.948(1)

36

Krkrypton

83.798(2)

54

Xexenon

131.293(6)

86

Rnradon

[222]

22

Tititanium

47.867(1)

22

Tititanium

47.867(1)

40

Zrzirconium

91.224(2)

72

Hfhafnium

178.49(2)

104

Rfrutherfordium

[261]

23

Vvanadium

50.9415(1)

41

Nbniobium

92.906 38(2)

73

Tatantalum

180.9479(1)

105

Dbdubnium

[262]

24

Crchromium

51.9961(6)

24

Crchromium

51.9961(6)

42

Momolybdenum

95.94(2)

74

Wtungsten

183.84(1)

106

Sgseaborgium

[266]

25

Mnmanganese

54.938 049(9)

43

Tctechnetium

[98]

75

Rerhenium

186.207(1)

107

Bhbohrium

[264]

26

Feiron

55.845(2)

44

Ruruthenium

101.07(2)

76

Ososmium

190.23(3)

108

Hshassium

[277]

27

Cocobalt

58.933 200(9)

45

Rhrhodium

102.905 50(2)

77

Iriridium

192.217(3)

109

Mtmeitnerium

[268]

28

Ninickel

58.6934(2)

46

Pdpalladium

106.42(1)

78

Ptplatinum

195.078(2)

110

Dsdarmstadtium

[271]

29

Cucopper

63.546(3)

47

Agsilver

107.8682(2)

79

Augold

196.966 55(2)

30

Znzinc

65.409(4)

48

Cdcadmium

112.411(8)

80

Hgmercury

200.59(2)

111

Rgroentgenium

[272]

57

Lalanthanum

138.9055(2)

89

Acactinium

[227]

58

Cecerium

140.116(1)

90

Ththorium

232.0381(1)

59

Prpraseodymium

140.907 65(2)

91

Paprotactinium

231.035 88(2)

60

Ndneodymium

144.24(3)

92

Uuranium

238.028 91(3)

61

Pmpromethium

[145]

93

Npneptunium

[237]

62

Smsamarium

150.36(3)

94

Puplutonium

[244]

63

Eueuropium

151.964(1)

95

Amamericium

[243]

64

Gdgadolinium

157.25(3)

96

Cmcurium

[247]

65

Tbterbium

158.925 34(2)

97

Bkberkelium

[247]

66

Dydysprosium

162.500(1)

98

Cfcalifornium

[251]

67

Hoholmium

164.930 32(2)

99

Eseinsteinium

[252]

68

Ererbium

167.259(3)

100

Fmfermium

[257]

69

Tmthulium

168.934 21(2)

101

Mdmendelevium

[258]

70

Ybytterbium

173.04(3)

102

Nonobelium

[259]

71

Lulutetium

174.967(1)

103

Lrlawrencium

[262]

21

Scscandium

44.955 910(8)

39

Yyttrium

88.905 85(2)

57-71

lanthanoids

89-103

actinoids

atomic number

Symbol

standard atomic weight

2 13 14 15 16 17Key:

3 4 5 6 7 8 9 10 11 12

name

IUPAC Periodic Table of the Elements