📚 Reactivity of Metals | 金属活动性
Some metals fizz quickly in dilute acid, some burn with a bright white flame, and some appear to do almost nothing. Understanding the reactivity of metals helps you predict whether reactions happen, how fast they happen, and how metals are extracted from their ores.
有些金属在稀酸中会快速冒泡，有些会发出耀眼的白光燃烧，还有些几乎不发生任何变化。理解金属活动性可以帮助你预测反应是否发生、反应快慢，以及金属如何从矿石中提取。
1. What Does Reactivity Mean? | 什么是金属活动性？
Reactivity describes how easily a metal loses electrons to form positive ions. A more reactive metal gives away electrons more easily, so it forms compounds more readily and is harder to extract from its ore.
金属活动性描述金属失去电子形成阳离子的难易程度。越活泼的金属越容易失去电子，因此更容易形成化合物，也越难从矿石中提取。
For example, potassium reacts violently with water, while gold can stay shiny and unchanged for thousands of years. This difference is due to their positions in the reactivity series.
例如，钾遇水会发生剧烈反应，而金可以保持光亮数千年不变。这种差异正是由于它们在金属活动性顺序中的位置不同。
2. The Reactivity Series | 金属活动性顺序
The reactivity series lists metals in order of how vigorously they react. Carbon and hydrogen are often included as reference points because they are used to predict displacement and extraction reactions.
金属活动性顺序将金属按照反应剧烈程度排列。碳和氢通常作为参照点列入其中，因为它们可用于预测置换反应和冶炼反应。
| Most Reactive | 最活泼 | Least Reactive | 最不活泼 |
|---|---|
| Potassium (K), Sodium (Na), Calcium (Ca), Magnesium (Mg), Aluminium (Al), Carbon (C), Zinc (Zn), Iron (Fe), Tin (Sn), Lead (Pb), Hydrogen (H), Copper (Cu), Silver (Ag), Gold (Au), Platinum (Pt) |
A common way to remember the first few metals is: Please Send Cats, Monkeys And Cute Zebras Into Hot Countries Signed General Penguin.
一个常见记忆口诀：钾钠钙镁铝，碳锌铁锡铅，氢铜银铂金。活泼性从前往后依次减弱。
3. Reaction with Oxygen | 与氧气反应
Most metals react with oxygen to form metal oxides. The speed and violence of the reaction depend on the metal’s reactivity. Potassium and sodium tarnish quickly in air, while gold does not react with oxygen at all.
大多数金属与氧气反应生成金属氧化物。反应的速度和剧烈程度取决于金属的活泼性。钾和钠在空气中很快失去光泽，而金完全不会与氧气反应。
Magnesium burns in air with a bright white flame to form white magnesium oxide:
镁在空气中燃烧，发出耀眼的白光，生成白色氧化镁：
2Mg + O₂ → 2MgO
Copper reacts slowly when heated to form black copper(II) oxide:
铜在加热时缓慢反应，生成黑色氧化铜：
2Cu + O₂ → 2CuO
Aluminium also reacts with oxygen, forming a thin layer of aluminium oxide that protects the metal underneath from further reaction.
铝也会与氧气反应，形成一层薄薄的氧化铝，保护内部的铝不再继续反应。
4. Reaction with Water | 与水反应
Only the more reactive metals react with water at room temperature. Potassium, sodium and calcium react with cold water; magnesium reacts very slowly with cold water, but faster with steam. Less reactive metals such as iron and zinc react with steam, while copper, silver and gold do not react with water.
只有比较活泼的金属才能在室温下与水反应。钾、钠和钙能与冷水反应；镁与冷水反应很慢，但与水蒸气反应较快。铁和锌等活泼性较低的金属可与水蒸气反应，而铜、银和金不与水反应。
Sodium reacts vigorously with cold water to form sodium hydroxide and hydrogen gas:
钠与冷水剧烈反应，生成氢氧化钠和氢气：
2Na + 2H₂O → 2NaOH + H₂
Calcium reacts steadily with water to form calcium hydroxide and hydrogen gas:
钙与水稳定反应，生成氢氧化钙和氢气：
Ca + 2H₂O → Ca(OH)₂ + H₂
5. Reaction with Dilute Acids | 与稀酸反应
Many metals react with dilute hydrochloric acid or dilute sulfuric acid to produce a salt and hydrogen gas. The test for hydrogen is to hold a burning splint at the mouth of the test tube; it burns with a squeaky pop.
许多金属与稀盐酸或稀硫酸反应，生成盐和氢气。检验氢气的方法是：将点燃的木条靠近试管口，氢气会发出“噗”的爆鸣声。
Magnesium reacts rapidly with dilute hydrochloric acid:
镁与稀盐酸反应迅速：
Mg + 2HCl → MgCl₂ + H₂
Zinc reacts with dilute sulfuric acid to produce zinc sulfate and hydrogen:
锌与稀硫酸反应生成硫酸锌和氢气：
Zn + H₂SO₄ → ZnSO₄ + H₂
Copper, silver and gold do not react with dilute acids, which is why copper is sometimes used for water pipes and gold is used for jewellery.
铜、银和金不与稀酸反应，因此铜常用于水管，金常用于首饰。
6. Displacement Reactions | 置换反应
A more reactive metal can displace a less reactive metal from a compound in solution. For example, if an iron nail is placed in blue copper(II) sulfate solution, the nail becomes coated with brown copper and the blue solution fades.
更活泼的金属能把较不活泼的金属从其化合物的溶液中置换出来。例如，将铁钉放入蓝色的硫酸铜溶液中，铁钉表面会覆盖一层红棕色的铜，蓝色溶液逐渐变浅。
Fe + CuSO₄ → FeSO₄ + Cu
Zinc is more reactive than copper, so it can displace copper from copper(II) sulfate solution:
锌比铜活泼，因此它可以从硫酸铜溶液中置换出铜：
Zn + CuSO₄ → ZnSO₄ + Cu
Copper cannot displace zinc from zinc sulfate solution because copper is less reactive than zinc. Displacement reactions provide evidence for the reactivity series.
铜不能从硫酸锌溶液中置换出锌，因为铜不如锌活泼。置换反应为金属活动性顺序提供了证据。
7. Reactivity and Extraction of Metals | 金属活泼性与冶炼
The method used to extract a metal from its ore depends on its reactivity. Metals more reactive than carbon, such as aluminium, are extracted by electrolysis. Metals less reactive than carbon, such as iron, can be extracted by heating with carbon.
从矿石中提取金属的方法取决于金属的活动性。比碳更活泼的金属（如铝）通过电解法提取。不如碳活泼的金属（如铁）可通过与碳共热来提取。
Very unreactive metals such as gold and silver are found native in the Earth, meaning they occur as uncombined elements. This is why ancient peoples could obtain gold without advanced technology.
金和银等极不活泼的金属以单质形式存在于自然界中。这就是古代人在没有先进技术的情况下也能获得黄金的原因。
8. Corrosion and Rusting | 腐蚀与生锈
Corrosion is the gradual destruction of a metal by chemical reactions with substances in the environment. Rusting is the specific corrosion of iron and steel, and it requires both oxygen and water.
腐蚀是金属与环境中的物质发生化学反应而逐渐被破坏的过程。生锈是铁和钢的特定腐蚀现象，它需要氧气和水同时存在。
Some metals appear to corrode quickly at first, but form a protective oxide layer. Aluminium forms a thin coat of aluminium oxide that prevents further reaction, while iron rust flakes away and exposes fresh metal to further rusting.
有些金属起初似乎腐蚀很快，但会形成一层保护性氧化膜。铝会形成一层薄的氧化铝，阻止进一步反应；而铁锈会剥落，露出新的金属表面，导致继续生锈。
9. Investigating Reactivity in the Lab | 实验室探究金属活动性
A common practical investigation adds equal-sized pieces of different metals to the same dilute acid. The rate of hydrogen bubbles or the temperature change is measured and compared.
常见的实验探究方法是：将大小相同的不同金属片放入相同的稀酸中，测量气泡产生的速率或温度变化，并加以比较。
Control variables include the concentration and volume of acid, the temperature of the solution, and the surface area and mass of each metal. A faster stream of bubbles indicates a more reactive metal.
需要控制的变量包括酸的浓度和体积、溶液温度、每种金属的表面积和质量。气泡产生越快，说明金属越活泼。
10. Key Summary and Exam Tips | 总结与考试技巧
Remember that the reactivity series predicts whether a metal will react with oxygen, water or acid, and whether a displacement reaction will occur. Always write balanced symbol equations where possible and include state symbols if your exam requires them.
请记住：金属活动性顺序可以预测金属是否会与氧气、水或酸反应，以及置换反应是否会发生。尽可能写出配平的化学方程式，如果考试要求，还需标注状态符号。
Common mistakes include forgetting that hydrogen gas is produced when a metal reacts with an acid, or saying that carbon is a metal. Carbon is a non-metal reference point used in extraction and displacement.
常见错误包括：忘记金属与酸反应会生成氢气，或误以为碳是金属。碳是用于冶炼和置换反应中的非金属参照物。
Practise writing equations for reactions of metals with oxygen, water and acids, and link each observation back to the reactivity series.
多练习书写金属与氧气、水和酸反应的方程式，并将每个实验现象与金属活动性顺序联系起来。
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