📚 The Reactivity Series | 反应性序列
The reactivity series is a list of metals arranged in order of how vigorously they react with other substances, such as oxygen, water, and acids. It helps chemists predict whether a metal will take part in a reaction, how a metal can be extracted from its ore, and how easily a metal will corrode. This guide explains the order itself, the key reactions behind it, and how to use it confidently in written and practical exam questions.
反应性序列是一张按金属与其他物质（如氧气、水和酸）反应的剧烈程度排列的金属顺序表。它帮助化学家预测金属是否会参与反应、金属如何从矿石中提取，以及金属腐蚀的难易程度。本文讲解序列本身、背后的关键反应，以及如何在书面题和实验题中熟练运用它。
1. What Is the Reactivity Series? | 什么是反应性序列？
The reactivity series is a way of arranging metals in order of their reactivity, from the most reactive to the least reactive. A metal's reactivity describes how easily it loses electrons and forms positive ions in chemical reactions.
反应性序列是将金属按照活泼性从强到弱排列的一种方式。金属的活泼性描述它在化学反应中失去电子并形成正离子的难易程度。
In KS3 Chemistry, a common order is: potassium, sodium, calcium, magnesium, aluminium, carbon, zinc, iron, lead, hydrogen, copper, silver, gold.
在 KS3 化学中，常见顺序为：钾、钠、钙、镁、铝、碳、锌、铁、铅、氢、铜、银、金。
The series is not just a memory list. Every position on it is fixed by observable evidence: how fast a metal bubbles in acid, how violently it reacts with cold water, and whether it can push another metal out of its compound.
这张序列并不只是一份背诵清单。序列上的每一个位置都由可观察的证据确定：金属在酸中冒气泡的快慢、与冷水反应的剧烈程度，以及它能否把另一种金属从其化合物中置换出来。
2. The Standard Order of Metals | 金属的标准顺序
The list below shows the metals from most reactive at the top to least reactive at the bottom. Carbon and hydrogen are written in brackets because they are non-metals, but they act as important dividing lines.
下面的列表从最活泼（顶端）到最不活泼（底端）排列。碳和氢用括号标出，因为它们是非金属，但它们充当重要的分界线。
- Potassium (K) — reacts violently with cold water 钾：与冷水剧烈反应
- Sodium (Na) — reacts vigorously with cold water 钠：与冷水强烈反应
- Calcium (Ca) — reacts steadily with cold water 钙：与冷水稳定反应
- Magnesium (Mg) — reacts very slowly with cold water, fast with steam 镁：与冷水极慢反应，与水蒸气反应快
- Aluminium (Al) — reactive, but protected by an oxide layer 铝：活泼，但有氧化层保护
- (Carbon, C) — non-metal reference point 碳：非金属参照点
- Zinc (Zn) — reacts with steam and with dilute acid 锌：与水蒸气、稀酸反应
- Iron (Fe) — reacts slowly with steam and dilute acid 铁：与水蒸气、稀酸缓慢反应
- (Hydrogen, H) — non-metal reference point 氢：非金属参照点
- Lead (Pb) — reacts very slowly with dilute acid 铅：与稀酸极缓慢反应
- Copper (Cu) — no reaction with water or dilute acid 铜：与水、稀酸不反应
- Silver (Ag) and Gold (Au) — almost completely unreactive 银和金：几乎完全不活泼
Different textbooks place lead and carbon in slightly different positions, but the relative order of the metals never changes. Learn the metals first, then add the two bracketed non-metals.
不同教材对铅和碳的位置安排略有差异，但金属之间的相对顺序从不改变。先记住金属，再把括号中的两种非金属加进去。
3. Why Metals React: Losing Electrons | 金属为何反应：失去电子
All metals react in the same basic way: they lose electrons to form positive ions. A more reactive metal loses electrons more readily, so its atoms give up electrons to almost anything nearby.
所有金属的基本反应方式相同：失去电子形成正离子。越活泼的金属越容易失去电子，因此它的原子几乎会把电子交给身边的任何物质。
Metal atom − electrons → positive ion
a − e⁻ → Na⁺ Mg − 2e⁻ → Mg²⁺ Al − 3e⁻ → Al³⁺
Potassium loses its outer electron so easily that it must be stored in oil to keep it away from air and moisture. Gold holds its electrons so tightly that it can sit in air for centuries without changing.
钾极易失去最外层电子，因此必须保存在煤油中，避免接触空气和水分。金对电子束缚很紧，可以在空气中放置数百年而不发生变化。
4. Reactions with Oxygen | 与氧气的反应
Most metals react with oxygen to form a metal oxide. The more reactive the metal, the faster and more dramatic the reaction.
大多数金属与氧气反应生成金属氧化物。金属越活泼，反应越快、现象越剧烈。
metal + oxygen → metal oxide
+ O₂ → 2Na₂O 2Mg + O₂ → 2MgO 2Cu + O₂ → 2CuO
Potassium and sodium tarnish within seconds in air. Magnesium burns with a brilliant white flame and leaves a white powder. Iron reacts slowly to form rust rather than burning. Copper only forms a black coating when heated strongly, and gold shows no change at all.
钾和钠在空气中几秒内就会失去光泽。镁燃烧发出耀眼白光，留下白色粉末。铁缓慢反应生成铁锈，而不是燃烧。铜只有强热时才形成黑色覆盖层，金则毫无变化。
5. Reactions with Water and Steam | 与水和水蒸气的反应
The way a metal behaves with water is one of the clearest tests of reactivity. Metals above magnesium in the series react with cold water; metals between magnesium and iron need steam; metals below hydrogen do not react at all.
金属与水的行为是检验活泼性最清晰的方法之一。序列中位于镁以上的金属能与冷水反应；镁到铁之间的金属需要水蒸气；氢以下的金属完全不反应。
2Na + 2H₂O → 2NaOH + H₂
Ca + 2H₂O → Ca(OH)₂ + H₂
Mg + H₂O(g) → MgO + H₂ Zn + H₂O(g) → ZnO + H₂
Potassium and sodium fizz furiously, sometimes catching fire, and the resulting solution is strongly alkaline. Calcium sinks and bubbles steadily. Magnesium barely reacts with cold water but burns brightly in steam. Zinc and iron react only with steam, and copper, silver and gold do nothing.
钾和钠剧烈冒泡，有时会燃烧，生成的溶液呈强碱性。钙会下沉并稳定冒泡。镁与冷水几乎不反应，但在水蒸气中会明亮燃烧。锌和铁只与水蒸气反应，铜、银、金则不反应。
6. Reactions with Dilute Acids | 与稀酸的反应
Metals above hydrogen in the series react with dilute hydrochloric acid or dilute sulfuric acid to produce a salt and hydrogen gas. Metals below hydrogen are pushed out of the way and no reaction occurs.
序列中位于氢以上的金属能与稀盐酸或稀硫酸反应，生成盐和氢气。氢以下的金属则被排除在外，不发生反应。
metal + acid → salt + hydrogen
Mg + 2HCl → MgCl₂ + H₂ Zn + 2HCl → ZnCl₂ + H₂
Fe + 2HCl → FeCl₂ + H₂ 2Al + 6HCl → 2AlCl₃ + 3H₂
The test for the gas is a lighted splint, which gives a squeaky pop. Reaction speed follows the series exactly: magnesium is fastest and most vigorous, zinc is moderate, iron is slow, lead is barely perceptible, and copper, silver and gold give no bubbles at all.
检验氢气的方法是用点燃的木条，会发出"爆鸣声"。反应速率完全遵循序列：镁最快最剧烈，锌适中，铁缓慢，铅几乎看不出变化，而铜、银、金完全不产生气泡。
7. Displacement Reactions | 置换反应
A more reactive metal can displace a less reactive metal from a solution of its salt. This is one of the most reliable ways to confirm the order of the reactivity series in the laboratory.
较活泼的金属可以把较不活泼的金属从其盐溶液中置换出来。这是实验室中确认反应性序列顺序最可靠的方法之一。
Zn + CuSO₄ → ZnSO₄ + Cu Fe + CuSO₄ → FeSO₄ + Cu
Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag
When zinc is placed in blue copper(II) sulfate solution, the blue colour fades and a pink-brown layer of copper appears on the zinc. The reverse reaction, copper in zinc sulfate solution, produces no change at all.
把锌放入蓝色的硫酸铜(II)溶液中，蓝色会逐渐褪去，锌表面出现粉棕色的铜。相反地，把铜放入硫酸锌溶液中则毫无变化。
The rule is simple: only a metal higher in the series can displace one lower down, never the other way round. Silver nitrate is usually chosen for copper because silver sits well below copper in the series.
规律很简单：只有位置靠上的金属才能置换位置靠下的金属，反之则不行。铜的实验中通常选用硝酸银，因为银的位置远在铜之下。
8. Carbon and Hydrogen as Reference Points | 碳和氢作为参照点
Carbon and hydrogen are not metals, but they are included as useful reference points. Carbon helps explain which metal oxides can be reduced by heating, and hydrogen helps predict acid reactions.
碳和氢不是金属，但作为有用的参照点被列入序列。碳有助于解释哪些金属氧化物可以通过加热还原，氢则有助于预测金属与酸的反应。
Any metal oxide below carbon can be reduced by heating it with carbon. Any metal above carbon is too tightly bonded to its oxygen, so carbon cannot remove the oxygen and electrolysis is needed instead.
位于碳以下的金属氧化物可以通过与碳共热而被还原。位于碳以上的金属与氧结合得太牢固，碳无法夺走氧，必须改用电解法。
Hydrogen marks the acid line. A metal above hydrogen releases hydrogen gas from dilute acid; a metal below hydrogen does not. In displacement terms, any metal above hydrogen can also displace hydrogen from water or acid.
氢是酸的界线。氢以上的金属能从稀酸中放出氢气，氢以下的金属不能。就置换而言，氢以上的任何金属也能把水或酸中的氢置换出来。
9. Extracting Metals from Their Ores | 从矿石中提取金属
The position of a metal in the reactivity series decides how it must be extracted. The more reactive the metal, the harder it is to separate from its compound, and the more energy the process costs.
金属在反应性序列中的位置决定了它的提取方法。金属越活泼，越难从化合物中分离出来，工艺耗费的能量也越多。
| Position | 位置 | Method | 提取方法 | Example | 例子 |
|---|---|---|
| Above carbon | 碳以上 | Electrolysis of the molten compound | 电解熔融化合物 | Aluminium from aluminium oxide | 从氧化铝提取铝 |
| Below carbon, above hydrogen | 碳以下、氢以上 | Reduction with carbon or carbon monoxide | 用碳或一氧化碳还原 | Iron from iron(III) oxide | 从氧化铁(III)提取铁 |
| Around hydrogen | 接近氢 | Reduction or displacement | 还原或置换 | Copper from copper compounds | 从铜化合物提取铜 |
| Very low | 极低 | Found native, no extraction needed | 以单质形式存在，无需提取 | Gold, silver | 金、银 |
Fe₂O₃ + 3CO → 2Fe + 3CO₂
2Fe₂O₃ + 3C → 4Fe + 3CO₂ ZnO + C → Zn + CO
This is why an iron nail is cheap and a gold ring is not: iron is grabbed from its ore by carbon in a blast furnace, while gold is simply dug out of the ground.
这就是铁钉便宜而金戒指昂贵的原因：铁在鼓风炉中由碳从矿石里夺出，而金只需从地下直接开采。
10. Corrosion and Rusting | 腐蚀与生锈
Corrosion happens when a metal is attacked by substances in its surroundings. In general, the more reactive a metal is, the more easily it corrodes, but there are important exceptions that examiners like to test.
腐蚀是指金属受到周围物质侵蚀的过程。一般来说，金属越活泼越容易腐蚀，但存在一些考试常考的重要例外。
iron + oxygen + water → hydrated iron(III) oxide
Rusting needs both oxygen and water. Dry air alone or pure water alone will not rust iron, but together they produce the familiar orange-brown flaking layer that eventually weakens a structure.
铁生锈需要氧气和水同时存在。只有干燥空气或只有纯水都不会使铁生锈，但两者同时存在就会生成熟悉的橙棕色剥落层，最终削弱结构强度。
Aluminium is the classic exception: it is more reactive than zinc and iron, yet it resists corrosion because a thin, tough oxide layer forms instantly and seals the surface. Gold and silver resist corrosion simply because they are unreactive.
铝是典型的例外：它比锌和铁更活泼，却耐腐蚀，因为表面会立即形成一层薄而坚韧的氧化层将其封闭。金和银耐腐蚀则仅仅是因为它们不活泼。
A more reactive metal can also protect a less reactive one by acting as a sacrificial metal. Zinc coating on steel, known as galvanising, protects iron even if the coating is scratched.
较活泼的金属还可以充当牺牲金属来保护较不活泼的金属。钢表面的镀锌层即使被划破，仍能保护内部的铁。
11. Quick-Reference Summary Table | 速查总结表
Use this table to check the behaviour of each metal at a glance before an exam or a practical lesson.
考试或实验课前，可用下表快速核验每种金属的行为。
| Metal | 金属 | style="border:
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