元素周期表
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电子排布表示原子的电子在电子层和亚层中的排列方式。这张图以稀有气体简写形式给出每种元素的基态电子排布,例如你可以读出钠是 [Ne] 3s¹:即氖的电子再加上 3s 亚层中的一个电子。
如何读电子排布
电子排布的每一部分都指明一个亚层及其中的电子数。在 1s² 2s² 2p⁶ 中,第一个数字是电子层(能级),字母是亚层的类型,上标是电子数。s 亚层最多容纳 2 个电子,p 容纳 6 个,d 容纳 10 个,f 容纳 14 个,所有上标之和总是等于原子序数。
写出每个亚层会很冗长,所以这张表使用稀有气体简写:方括号中前一个稀有气体的符号代表它的全部电子。硫的 1s² 2s² 2p⁶ 3s² 3p⁴ 写成 [Ne] 3s² 3p⁴。单元格按区着色,每个单元格显示该元素的电子排布。
填充顺序
电子先填充能量最低的亚层,这条规则叫做构造原理。顺序是 1s、2s、2p、3s、3p、4s、3d、4p、5s、4d、5p、6s、4f、5d、6p、7s、5f、6d、7p,所以 4s 先于 3d 填充,4f 只在 6s 之后填充。你不需要背下来:从左到右阅读每一个周期,就会按填充顺序依次经过各个区,从 s 区到 f 区(位于底部第 6 和第 7 周期的那两行)、d 区,再到 p 区。
这张表按电子层序号而不是填充顺序来书写亚层,所以铁写作 [Ar] 3d⁶ 4s²。过渡金属形成离子时,先失去最外层的 s 电子,所以 Fe²⁺ 是 [Ar] 3d⁶。
规则的例外
大约有二十种元素不遵循简单的填充顺序。最著名的是铬 [Ar] 3d⁵ 4s¹ 和铜 [Ar] 3d¹⁰ 4s¹,其中一个电子从 4s 移入 3d,使 d 亚层恰好半充满或全充满。银和金与铜的情形相同,而钯 [Kr] 4d¹⁰ 在最外层 s 亚层中完全没有电子。超重元素的电子排布是计算得出的预测,而不是测量结果。
实例:氯
元素的位置能告诉你它的电子排布。除钯以外,周期数就是容纳电子的最外层的序号,而所在的区则告诉你哪个亚层正在被填充。氯位于第 3 周期,是 p 区的第五个元素,所以它的电子排布以 3p⁵ 结尾:1s² 2s² 2p⁶ 3s² 3p⁵,即 [Ne] 3s² 3p⁵。上标之和为 17,正是氯的原子序数,它的最外层有 2 + 5 = 7 个价电子。
全部 118 种元素的电子排布
点击列标题可排序。
| 1 | 氢 | H | 1s1 | 1 |
| 2 | 氦 | He | 1s2 | 2 |
| 3 | 锂 | Li | [He] 2s1 | 2, 1 |
| 4 | 铍 | Be | [He] 2s2 | 2, 2 |
| 5 | 硼 | B | [He] 2s2 2p1 | 2, 3 |
| 6 | 碳 | C | [He] 2s2 2p2 | 2, 4 |
| 7 | 氮 | N | [He] 2s2 2p3 | 2, 5 |
| 8 | 氧 | O | [He] 2s2 2p4 | 2, 6 |
| 9 | 氟 | F | [He] 2s2 2p5 | 2, 7 |
| 10 | 氖 | Ne | [He] 2s2 2p6 | 2, 8 |
| 11 | 钠 | Na | [Ne] 3s1 | 2, 8, 1 |
| 12 | 镁 | Mg | [Ne] 3s2 | 2, 8, 2 |
| 13 | 铝 | Al | [Ne] 3s2 3p1 | 2, 8, 3 |
| 14 | 硅 | Si | [Ne] 3s2 3p2 | 2, 8, 4 |
| 15 | 磷 | P | [Ne] 3s2 3p3 | 2, 8, 5 |
| 16 | 硫 | S | [Ne] 3s2 3p4 | 2, 8, 6 |
| 17 | 氯 | Cl | [Ne] 3s2 3p5 | 2, 8, 7 |
| 18 | 氩 | Ar | [Ne] 3s2 3p6 | 2, 8, 8 |
| 19 | 钾 | K | [Ar] 4s1 | 2, 8, 8, 1 |
| 20 | 钙 | Ca | [Ar] 4s2 | 2, 8, 8, 2 |
| 21 | 钪 | Sc | [Ar] 3d1 4s2 | 2, 8, 9, 2 |
| 22 | 钛 | Ti | [Ar] 3d2 4s2 | 2, 8, 10, 2 |
| 23 | 钒 | V | [Ar] 3d3 4s2 | 2, 8, 11, 2 |
| 24 | 铬 | Cr | [Ar] 3d5 4s1 | 2, 8, 13, 1 |
| 25 | 锰 | Mn | [Ar] 3d5 4s2 | 2, 8, 13, 2 |
| 26 | 铁 | Fe | [Ar] 3d6 4s2 | 2, 8, 14, 2 |
| 27 | 钴 | Co | [Ar] 3d7 4s2 | 2, 8, 15, 2 |
| 28 | 镍 | Ni | [Ar] 3d8 4s2 | 2, 8, 16, 2 |
| 29 | 铜 | Cu | [Ar] 3d10 4s1 | 2, 8, 18, 1 |
| 30 | 锌 | Zn | [Ar] 3d10 4s2 | 2, 8, 18, 2 |
| 31 | 镓 | Ga | [Ar] 3d10 4s2 4p1 | 2, 8, 18, 3 |
| 32 | 锗 | Ge | [Ar] 3d10 4s2 4p2 | 2, 8, 18, 4 |
| 33 | 砷 | As | [Ar] 3d10 4s2 4p3 | 2, 8, 18, 5 |
| 34 | 硒 | Se | [Ar] 3d10 4s2 4p4 | 2, 8, 18, 6 |
| 35 | 溴 | Br | [Ar] 3d10 4s2 4p5 | 2, 8, 18, 7 |
| 36 | 氪 | Kr | [Ar] 3d10 4s2 4p6 | 2, 8, 18, 8 |
| 37 | 铷 | Rb | [Kr] 5s1 | 2, 8, 18, 8, 1 |
| 38 | 锶 | Sr | [Kr] 5s2 | 2, 8, 18, 8, 2 |
| 39 | 钇 | Y | [Kr] 4d1 5s2 | 2, 8, 18, 9, 2 |
| 40 | 锆 | Zr | [Kr] 4d2 5s2 | 2, 8, 18, 10, 2 |
| 41 | 铌 | Nb | [Kr] 4d4 5s1 | 2, 8, 18, 12, 1 |
| 42 | 钼 | Mo | [Kr] 4d5 5s1 | 2, 8, 18, 13, 1 |
| 43 | 锝 | Tc | [Kr] 4d5 5s2 | 2, 8, 18, 13, 2 |
| 44 | 钌 | Ru | [Kr] 4d7 5s1 | 2, 8, 18, 15, 1 |
| 45 | 铑 | Rh | [Kr] 4d8 5s1 | 2, 8, 18, 16, 1 |
| 46 | 钯 | Pd | [Kr] 4d10 | 2, 8, 18, 18 |
| 47 | 银 | Ag | [Kr] 4d10 5s1 | 2, 8, 18, 18, 1 |
| 48 | 镉 | Cd | [Kr] 4d10 5s2 | 2, 8, 18, 18, 2 |
| 49 | 铟 | In | [Kr] 4d10 5s2 5p1 | 2, 8, 18, 18, 3 |
| 50 | 锡 | Sn | [Kr] 4d10 5s2 5p2 | 2, 8, 18, 18, 4 |
| 51 | 锑 | Sb | [Kr] 4d10 5s2 5p3 | 2, 8, 18, 18, 5 |
| 52 | 碲 | Te | [Kr] 4d10 5s2 5p4 | 2, 8, 18, 18, 6 |
| 53 | 碘 | I | [Kr] 4d10 5s2 5p5 | 2, 8, 18, 18, 7 |
| 54 | 氙 | Xe | [Kr] 4d10 5s2 5p6 | 2, 8, 18, 18, 8 |
| 55 | 铯 | Cs | [Xe] 6s1 | 2, 8, 18, 18, 8, 1 |
| 56 | 钡 | Ba | [Xe] 6s2 | 2, 8, 18, 18, 8, 2 |
| 57 | 镧 | La | [Xe] 5d1 6s2 | 2, 8, 18, 18, 9, 2 |
| 58 | 铈 | Ce | [Xe] 4f1 5d1 6s2 | 2, 8, 18, 19, 9, 2 |
| 59 | 镨 | Pr | [Xe] 4f3 6s2 | 2, 8, 18, 21, 8, 2 |
| 60 | 钕 | Nd | [Xe] 4f4 6s2 | 2, 8, 18, 22, 8, 2 |
| 61 | 钷 | Pm | [Xe] 4f5 6s2 | 2, 8, 18, 23, 8, 2 |
| 62 | 钐 | Sm | [Xe] 4f6 6s2 | 2, 8, 18, 24, 8, 2 |
| 63 | 铕 | Eu | [Xe] 4f7 6s2 | 2, 8, 18, 25, 8, 2 |
| 64 | 钆 | Gd | [Xe] 4f7 5d1 6s2 | 2, 8, 18, 25, 9, 2 |
| 65 | 铽 | Tb | [Xe] 4f9 6s2 | 2, 8, 18, 27, 8, 2 |
| 66 | 镝 | Dy | [Xe] 4f10 6s2 | 2, 8, 18, 28, 8, 2 |
| 67 | 钬 | Ho | [Xe] 4f11 6s2 | 2, 8, 18, 29, 8, 2 |
| 68 | 铒 | Er | [Xe] 4f12 6s2 | 2, 8, 18, 30, 8, 2 |
| 69 | 铥 | Tm | [Xe] 4f13 6s2 | 2, 8, 18, 31, 8, 2 |
| 70 | 镱 | Yb | [Xe] 4f14 6s2 | 2, 8, 18, 32, 8, 2 |
| 71 | 镥 | Lu | [Xe] 4f14 5d1 6s2 | 2, 8, 18, 32, 9, 2 |
| 72 | 铪 | Hf | [Xe] 4f14 5d2 6s2 | 2, 8, 18, 32, 10, 2 |
| 73 | 钽 | Ta | [Xe] 4f14 5d3 6s2 | 2, 8, 18, 32, 11, 2 |
| 74 | 钨 | W | [Xe] 4f14 5d4 6s2 | 2, 8, 18, 32, 12, 2 |
| 75 | 铼 | Re | [Xe] 4f14 5d5 6s2 | 2, 8, 18, 32, 13, 2 |
| 76 | 锇 | Os | [Xe] 4f14 5d6 6s2 | 2, 8, 18, 32, 14, 2 |
| 77 | 铱 | Ir | [Xe] 4f14 5d7 6s2 | 2, 8, 18, 32, 15, 2 |
| 78 | 铂 | Pt | [Xe] 4f14 5d9 6s1 | 2, 8, 18, 32, 17, 1 |
| 79 | 金 | Au | [Xe] 4f14 5d10 6s1 | 2, 8, 18, 32, 18, 1 |
| 80 | 汞 | Hg | [Xe] 4f14 5d10 6s2 | 2, 8, 18, 32, 18, 2 |
| 81 | 铊 | Tl | [Xe] 4f14 5d10 6s2 6p1 | 2, 8, 18, 32, 18, 3 |
| 82 | 铅 | Pb | [Xe] 4f14 5d10 6s2 6p2 | 2, 8, 18, 32, 18, 4 |
| 83 | 铋 | Bi | [Xe] 4f14 5d10 6s2 6p3 | 2, 8, 18, 32, 18, 5 |
| 84 | 钋 | Po | [Xe] 4f14 5d10 6s2 6p4 | 2, 8, 18, 32, 18, 6 |
| 85 | 砹 | At | [Xe] 4f14 5d10 6s2 6p5 | 2, 8, 18, 32, 18, 7 |
| 86 | 氡 | Rn | [Xe] 4f14 5d10 6s2 6p6 | 2, 8, 18, 32, 18, 8 |
| 87 | 钫 | Fr | [Rn] 7s1 | 2, 8, 18, 32, 18, 8, 1 |
| 88 | 镭 | Ra | [Rn] 7s2 | 2, 8, 18, 32, 18, 8, 2 |
| 89 | 锕 | Ac | [Rn] 6d1 7s2 | 2, 8, 18, 32, 18, 9, 2 |
| 90 | 钍 | Th | [Rn] 6d2 7s2 | 2, 8, 18, 32, 18, 10, 2 |
| 91 | 镤 | Pa | [Rn] 5f2 6d1 7s2 | 2, 8, 18, 32, 20, 9, 2 |
| 92 | 铀 | U | [Rn] 5f3 6d1 7s2 | 2, 8, 18, 32, 21, 9, 2 |
| 93 | 镎 | Np | [Rn] 5f4 6d1 7s2 | 2, 8, 18, 32, 22, 9, 2 |
| 94 | 钚 | Pu | [Rn] 5f6 7s2 | 2, 8, 18, 32, 24, 8, 2 |
| 95 | 镅 | Am | [Rn] 5f7 7s2 | 2, 8, 18, 32, 25, 8, 2 |
| 96 | 锔 | Cm | [Rn] 5f7 6d1 7s2 | 2, 8, 18, 32, 25, 9, 2 |
| 97 | 锫 | Bk | [Rn] 5f9 7s2 | 2, 8, 18, 32, 27, 8, 2 |
| 98 | 锎 | Cf | [Rn] 5f10 7s2 | 2, 8, 18, 32, 28, 8, 2 |
| 99 | 锿 | Es | [Rn] 5f11 7s2 | 2, 8, 18, 32, 29, 8, 2 |
| 100 | 镄 | Fm | [Rn] 5f12 7s2 | 2, 8, 18, 32, 30, 8, 2 |
| 101 | 钔 | Md | [Rn] 5f13 7s2 | 2, 8, 18, 32, 31, 8, 2 |
| 102 | 锘 | No | [Rn] 5f14 7s2 | 2, 8, 18, 32, 32, 8, 2 |
| 103 | 铹 | Lr | [Rn] 5f14 7s2 7p1 | 2, 8, 18, 32, 32, 8, 3 |
| 104 | 𬬻 | Rf | [Rn] 5f14 6d2 7s2 | 2, 8, 18, 32, 32, 10, 2 |
| 105 | 𬭊 | Db | [Rn] 5f14 6d3 7s2 | 2, 8, 18, 32, 32, 11, 2 |
| 106 | 𬭳 | Sg | [Rn] 5f14 6d4 7s2 | 2, 8, 18, 32, 32, 12, 2 |
| 107 | 𬭛 | Bh | [Rn] 5f14 6d5 7s2 | 2, 8, 18, 32, 32, 13, 2 |
| 108 | 𬭶 | Hs | [Rn] 5f14 6d6 7s2 | 2, 8, 18, 32, 32, 14, 2 |
| 109 | 鿏 | Mt | [Rn] 5f14 6d7 7s2 | 2, 8, 18, 32, 32, 15, 2 |
| 110 | 𫟼 | Ds | [Rn] 5f14 6d8 7s2 | 2, 8, 18, 32, 32, 16, 2 |
| 111 | 𬬭 | Rg | [Rn] 5f14 6d9 7s2 | 2, 8, 18, 32, 32, 17, 2 |
| 112 | 鿔 | Cn | [Rn] 5f14 6d10 7s2 | 2, 8, 18, 32, 32, 18, 2 |
| 113 | 鿭 | Nh | [Rn] 5f14 6d10 7s2 7p1 | 2, 8, 18, 32, 32, 18, 3 |
| 114 | 鈇 | Fl | [Rn] 5f14 6d10 7s2 7p2 | 2, 8, 18, 32, 32, 18, 4 |
| 115 | 镆 | Mc | [Rn] 5f14 6d10 7s2 7p3 | 2, 8, 18, 32, 32, 18, 5 |
| 116 | 鉝 | Lv | [Rn] 5f14 6d10 7s2 7p4 | 2, 8, 18, 32, 32, 18, 6 |
| 117 | 鿬 | Ts | [Rn] 5f14 6d10 7s2 7p5 | 2, 8, 18, 32, 32, 18, 7 |
| 118 | 鿫 | Og | [Rn] 5f14 6d10 7s2 7p6 | 2, 8, 18, 32, 32, 18, 8 |