未發現元素列表
未發現元素在週期表中的位置

条目：扩展元素周期表
目前實驗合成原子序最大的元素可能是第七週期的最後一個元素118Og，而若發現了原子序数更大的元素則將被置於第八週期。根據格倫·西奧多·西博格於1969年提出的擴展元素週期表，在第八週期以後的週期中，將會有g區元素的出現，即有部份的元素會存在有g軌域的電子，然而第八週期以後的元素都尚未能被合成或發現，所以此理論迄今未能被驗證。
我們可以預測下表的g區元素可能位於f區元素的左方，下表先依主流予以採用︰
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 族未定 | 族未定 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| 週期未定 | 0 Nu 0號元素 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
|  | 1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 18 |
| 1 | 1 H 氢 | 2 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 13 | 14 | 15 | 16 | 17 | 2 He 氦 |
| 2 | 3 Li 锂 | 4 Be 铍 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5 B 硼 | 6 C 碳 | 7 N 氮 | 8 O 氧 | 9 F 氟 | 10 Ne 氖 |
| 3 | 11 Na 钠 | 12 Mg 镁 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 Al 铝 | 14 Si  | 15 P 磷 | 16 S 硫 | 17 Cl 氯 | 18 Ar 氩 |
| 4 | 19 K 钾 | 20 Ca 钙 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 21 Sc 钪 | 22 Ti 钛 | 23 V 钒 | 24 Cr 铬 | 25 Mn 锰 | 26 Fe 铁 | 27 Co 钴 | 28 Ni 镍 | 29 Cu 铜 | 30 Zn 锌 | 31 Ga 镓 | 32 Ge 锗 | 33 As 砷 | 34 Se 硒 | 35 Br 溴 | 36 Kr 氪 |
| 5 | 37 Rb 铷 | 38 Sr 锶 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 39 Y 钇 | 40 Zr 锆 | 41 Nb 铌 | 42 Mo 钼 | 43 Tc 锝 | 44 Ru 钌 | 45 Rh 铑 | 46 Pd 钯 | 47 Ag 银 | 48 Cd 镉 | 49 In 铟 | 50 Sn 锡 | 51 Sb 锑 | 52 Te 碲 | 53 I 碘 | 54 Xe 氙 |
| 6 | 55 Cs 铯 | 56 Ba 钡 |  | 57 La 镧 | 58 Ce 铈 | 59 Pr 镨 | 60 Nd 钕 | 61 Pm 钷 | 62 Sm 钐 | 63 Eu 铕 | 64 Gd 钆 | 65 Tb 铽 | 66 Dy 镝 | 67 Ho 钬 | 68 Er 铒 | 69 Tm 铥 | 70 Yb 镱 | 71 Lu  | 72 Hf 铪 | 73 Ta 钽 | 74 W 钨 | 75 Re 铼 | 76 Os 锇 | 77 Ir 铱 | 78 Pt 铂 | 79 Au 金 | 80 Hg 汞 | 81 Tl 铊 | 82 Pb 铅 | 83 Bi 铋 | 84 Po 钋 | 85 At  | 86 Rn 氡 |
| 7 | 87 Fr  | 88 Ra 镭 |  | 89 Ac 锕 | 90 Th 钍 | 91 Pa 镤 | 92 U 铀 | 93 Np 镎 | 94 Pu 鈽 | 95 Am 镅 | 96 Cm 锔 | 97 Bk  | 98 Cf 锎 | 99 Es 锿 | 100 Fm 镄 | 101 Md 钔 | 102 No 锘 | 103 Lr 铹 | 104 Rf  | 105 Db  | 106 Sg  | 107 Bh  | 108 Hs  | 109 Mt  | 110 Ds  | 111 Rg 錀 | 112 Cn 鎶 | 113 Nh  | 114 Fl  | 115 Mc  | 116 Lv  | 117 Ts  | 118 Og 鿫 |
| 8 | 119 Uue | 120 Ubn | g區元素 | 141 Uqu | 142 Uqb | 143 Uqt | 144 Uqq | 145 Uqp | 146 Uqh | 147 Uqs | 148 Uqo | 149 Uqe | 150 Upn | 151 Upu | 152 Upb | 153 Upt | 154 Upq | 155 Upp | 156 Uph | 157 Ups | 158 Upo | 159 Upe | 160 Uhn | 161 Uhu | 162 Uhb | 163 Uht | 164 Uhq |  |  |  |  |  |  |
| 9 | 165 Uhp | 166 Uhh |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 167 Uhs | 168 Uho | 169 Uhe | 170 Usn | 171 Usu | 172 Usb |

|  |  |  |  |  |  | 8 | 121 Ubu | 122 Ubb | 123 Ubt | 124 Ubq | 125 Ubp | 126 Ubh | 127 Ubs | 128 Ubo | 129 Ube | 130 Utn | 131 Utu | 132 Utb | 133 Utt | 134 Utq | 135 Utp | 136 Uth | 137 Uts | 138 Uto | 139 Ute | 140 Uqn |  |  |  |  |  |  |  |

|  |  |  |  |  | 族未定 | 族未定 | 族未定 | 族未定 | 族未定 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| 週期未定 |  |  | 分區未定 | 分區未定 | 173 Ust | 174 Usq | 175 Usp | 176 Ush | 177 Uss | ... |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| --- | --- | --- | --- | --- | --- | --- | --- |
|   無電子 |   s區元素 |   p區元素 |   d區元素 |   ds區元素 |   f區元素 |   g區元素 |   超臨界原子 |
（未發現元素以較淺顔色顯示）