周期 6

55 Cs 铯 132.905 56 Ba 钡 137.33 57 La 镧 138.905 58 Ce 铈 140.116 59 Pr 镨 140.908 60 Nd 钕 144.24 61 Pm 钷 144.913 62 Sm 钐 150.4 63 Eu 铕 151.964 64 Gd 钆 157.25 65 Tb 铽 158.925 66 Dy 镝 162.5 67 Ho 钬 164.93 68 Er 铒 167.26 69 Tm 铥 168.934 70 Yb 镱 173.05 71 Lu 镥 174.967 72 Hf 铪 178.49 73 Ta 钽 180.948 74 W 钨 183.84 75 Re 铼 186.207 76 Os 锇 190.2 77 Ir 铱 192.22 78 Pt 铂 195.08 79 Au 金 196.967 80 Hg 汞 200.59 81 Tl 铊 204.383 82 Pb 铅 207 83 Bi 铋 208.98 84 Po 钋 208.982 85 At 砹 209.987 86 Rn 氡 222.018