THE CHEMICAL ELEMENTS - Archaeological Chemistry - page 446

Atomic Atomic

number Symbol Name Weight number Symbol Name Weight

23 V Vanadium 50.9 58 Ce Cerium 140.1

24 Cr Chromium 52.0 59 Pr Praseodymium140.9

25 Mn Manganese 54.9 60 Nd Neodymium 144.2

26 Fe Iron 55.8 61 Pm Promethium [145]

27 Co Cobalt 58.9 62 Sm Samarium 150.4

28 Ni Nickel 58.7 63 Eu Europium 151.9

29 Cu Copper 63.5 64 Gd Gadolinium 157.2

30 Zn Zinc 65.4 65 Tb Terbium 158.9

31 Ga Gallium 69.7 66 Dy Dysprosium 162.5

32 Ge Germanium 72.6 67 Ho Holmium 164.9

33 As Arsenic 74.9 68 Er Erbium 167.3

34 Se Selenium 78.9 69 Tm Thulium 168.9

35 Br Bromine 79.9 70 Yb Ytterbium 173.0

36 Kr Krypton 83.8 71 Lu Lutetium 174.9

37 Rb Rubidium 85.5 72 Hf Hafnium 178.5

38 Sr Strontium 87.6 73 Ta Tantalum 180.9

39 Y Yttrium 88.9 74 W Tungsten 183.9

40 Zr Zirconium 91.2 75 Re Rhenium 186.2

41 Nb Niobium 92.9 76 Os Osmium 190.2

42 Mo Molybdenum 95.9 77 Ir Iridium 192.2

43 Tc Technetium 97.9 78 Pt Platinum 195.1

44 Ru Ruthenium 101.1 79 Au Gold 196.9

45 Rh Rhodium 102.9 80 Hg Mercury 200.6

46 Pd Palladium 106.4 81 Tl Thallium 204.3

47 Ag Silver 107.9 82 Pb Lead 207.2

48 Cd Cadmium 112.4 83 Bi Bismuth 208.9

49 In Indium 114.8 84 Po Polonium [209]

50 Sn Tin 118.7 85 At Astatine [210]

51 Sb Antimony 121.8 86 Rn Radon [222]

52 Te Tellurium 127.6 87 Fr Francium [223]

53 I Iodine 126.9 88 Ra Radium [226]

54 Xe Xenon 131.3 89 Ac Actinium [227]

55 Cs Cesium 132.9 90 Th Thorium 232.0

56 Ba Barium 137.3 91 Pa Protactinium [231]

57 La Lanthanum 138.9 92 U Uranium 238.0

The atomic weight of atoms of the same element may differ, and atoms of
the same element, having an equal atomic number but different atomic
weights are said to be isotopes . Some elements occur in only one isotopic
form, whereas others have many isotopes. Some isotopes, known as radioac-
tive isotopes , are unstable: they undergo radioactive decay and transmute into
other elements.