定义Definition
氢是原子序数为 1 的化学元素，符号 H，是最轻、宇宙中最丰富的元素，约占宇宙普通物质质量的 74%。常温下氢单质为无色无味、极易燃的双原子气体 H₂。
Hydrogen is the chemical element with atomic number 1 and symbol H, the lightest element and the most abundant in the universe, about 74% of ordinary matter by mass. The element is a colourless, odourless, highly flammable diatomic gas, H₂.
元素数据Element data
| 原子序数Atomic number | 1 |
|---|---|
| 元素符号Symbol | H |
| 相对原子质量Standard atomic weight | 1.008 |
| 电子排布Electron configuration | 1s¹ |
| 族 / 周期 / 区Group / period / block | 1 / 1 / s |
| 电负性（鲍林）Electronegativity (Pauling) | 2.20 |
| 常见氧化态Common oxidation states | +1, −1 |
原子结构与周期性Atomic structure and periodicity
氢原子只有一个质子和一个电子，是唯一能精确求解薛定谔方程的原子，氢原子光谱推动了玻尔模型和量子力学的建立。氢有三种同位素：氕（¹H）、氘（²H，D）和放射性的氚（³H，T）。它在周期表中的位置有争议：失去电子像碱金属，得到电子形成 H⁻ 又像卤素。
The hydrogen atom has one proton and one electron and is the only atom for which the Schrödinger equation is solved exactly; its spectrum drove the Bohr model and quantum mechanics. It has three isotopes: protium (¹H), deuterium (²H, D) and radioactive tritium (³H, T). Its place in the periodic table is debated: losing an electron it resembles the alkali metals, while forming H⁻ it resembles the halogens.
发现与命名Discovery and naming
1766 年卡文迪什用金属与酸反应收集到“可燃空气”，并测定了它的密度。1783 年拉瓦锡发现它燃烧生成水，命名为 hydrogène（“成水者”）。中文“氢”取“轻气”之意。1898 年杜瓦首次液化氢气，1899 年又得到固态氢。
In 1766 Cavendish collected 'inflammable air' from metals and acids and measured its density. In 1783 Lavoisier found it burns to water and named it hydrogène, the water-former. The Chinese name 氢 comes from 轻气, light gas. Dewar first liquefied hydrogen in 1898 and solidified it in 1899.
单质性质与用途The element and its uses
H₂ 的 H–H 键能 436 kJ/mol，常温下较稳定，但与氧气混合（4–75%）点燃会爆炸。工业氢主要来自天然气蒸汽重整，约一半用于合成氨，其余用于石油加氢精制、合成甲醇和油脂氢化。电解水得到的“绿氢”和燃料电池被视为未来清洁能源的重要方向。
The H–H bond energy is 436 kJ/mol, so H₂ is fairly inert at room temperature, but mixtures with air (4–75%) explode on ignition. Industrial hydrogen comes mainly from steam reforming of natural gas; about half goes to ammonia synthesis and the rest to hydrotreating oil, methanol and hydrogenating fats. Green hydrogen from electrolysis and fuel cells are seen as key to future clean energy.
反应Reactions
氢气具有可燃性和还原性。
Hydrogen is flammable and a reducing agent.
实验室制氢
Laboratory preparation
还原氧化铜，黑色变红色
Reducing copper oxide, black to red
光照下爆炸性化合
Explosive combination in light
与活泼金属生成离子型氢化物（H 为 −1 价）
Forms ionic hydrides with active metals (H is −1)
化学性质Chemical properties
纯净氢气在空气中安静燃烧，淡蓝色火焰；不纯时点燃会爆炸，点燃前必须验纯。
Pure hydrogen burns quietly with a pale blue flame; impure hydrogen explodes, so test purity first.
在催化剂（Ni、Pd、Pt）作用下与不饱和有机物加成。
Adds to unsaturated organic compounds over Ni, Pd or Pt catalysts.
年表Timeline
- 1766
卡文迪什确认“可燃空气”为独立物质
Cavendish identifies inflammable air as a distinct substance
- 1783
拉瓦锡命名 hydrogène
Lavoisier names it hydrogène
- 1898
杜瓦液化氢气
Dewar liquefies hydrogen
- 1931
尤里发现氘
Urey discovers deuterium
- 1934
卢瑟福等人发现氚
Rutherford and co-workers discover tritium