📚 IGCSE WJEC Chemistry: End-of-Term Revision Checklist | IGCSE WJEC 化学：期末复习提纲
As the end of term approaches, this revision checklist will help you consolidate all key topics in the WJEC IGCSE Chemistry specification. Use it to identify your strengths and areas for improvement, and to structure your final review sessions. Each section covers essential concepts, common calculations, and the most frequently examined practical skills.
期末临近，这份复习提纲将帮助你巩固WJEC IGCSE化学大纲中的所有关键主题。你可以用它来发现自己的强项和需要加强的方面，并以此规划最终的复习安排。每个部分都涵盖了必考的核心概念、常见计算以及最高频的实验技能。
1. Atomic Structure and the Periodic Table | 原子结构与元素周期表
Atoms consist of a nucleus containing protons and neutrons, surrounded by electrons arranged in shells. The atomic number (Z) is the number of protons, which determines the element. The mass number (A) is the total number of protons and neutrons. Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons, giving them different mass numbers. Relative atomic mass (Aᵣ) takes into account the relative abundances of all the naturally occurring isotopes of an element.
原子由含有质子和中子的原子核以及分层排布的电子组成。原子序数（Z）就是质子数，它决定了元素的种类。质量数（A）是质子数和中子数之和。同位素是质子数相同而中子数不同的同种元素的原子，因此它们具有不同的质量数。相对原子质量（Aᵣ）考虑了元素所有天然同位素的相对丰度。
Electrons fill the lowest available energy levels first: the first shell holds up to 2 electrons, the second up to 8, and the third also up to 8 for the purpose of IGCSE. The electron arrangement determines an element’s position in the Periodic Table – the group number equals the number of electrons in the outer shell, and the period number equals the number of occupied shells.
电子优先填充能量最低的能级：第一层最多容纳2个电子，第二层最多8个，在IGCSE范围内第三层也最多容纳8个电子。电子排布决定元素在周期表中的位置——族数等于最外层电子数，周期数等于已占据的电子层数。
The Periodic Table arranges elements in order of increasing atomic number. Metals are found to the left and centre, while non‑metals are on the right. Key group trends you must know:
周期表按原子序数递增的顺序排列元素。金属位于左边和中间，非金属位于右边。你必须掌握的关键族趋势如下：
- Group 1 (alkali metals): reactivity increases down the group; they react vigorously with water to form a metal hydroxide and hydrogen; melting and boiling points decrease down the group.
- Group 7 (halogens): reactivity decreases down the group; a more reactive halogen can displace a less reactive halogen from its salt solution; melting and boiling points increase down the group.
- Group 0 (noble gases): these are chemically unreactive because they have a full outer electron shell; they are used in lighting and as inert atmospheres.
- 第1族（碱金属）：向下反应性增强；它们与水剧烈反应生成金属氢氧化物和氢气；熔点和沸点逐渐降低。
- 第7族（卤素）：向下反应性减弱；较活泼的卤素能将较不活泼的卤素从其盐溶液中置换出来；熔点和沸点逐渐升高。
- 第0族（稀有气体）：由于具有满的最外层电子结构，它们化学性质很不活泼；常用于照明和作为惰性气氛。
2. Bonding, Structure and Properties | 化学键、结构与性质
Ionic bonding occurs between metals and non‑metals. The metal atom loses electrons to form a positive ion (cation), while the non‑metal atom gains electrons to form a negative ion (anion). Ions are held together in a giant ionic lattice by strong electrostatic forces. Ionic compounds have high melting and boiling points and conduct electricity when molten or dissolved in water because the ions are free to move. They are often brittle and soluble in water.
离子键形成于金属和非金属之间。金属原子失去电子成为阳离子，非金属原子得到电子成为阴离子。离子通过强大的静电引力在巨型离子晶格中结合在一起。离子化合物具有高熔点和高沸点，在熔融或溶于水时能导电，因为此时离子可以自由移动。它们通常很脆，且可溶于水。
Covalent bonding involves the sharing of one or more pairs of electrons between non‑metal atoms. Substances with simple molecular structures, such as H₂O, CO₂, and CH₄, have low melting and boiling points because the intermolecular forces between molecules are weak. They do not conduct electricity, as there are no free charged particles. Giant covalent structures, such as diamond, graphite, and silicon dioxide (SiO₂), have very high melting points. In diamond, each carbon atom is bonded to four others in a rigid tetrahedral structure, making it extremely hard and non‑conducting. In graphite, each carbon atom bonds to three others, forming layers that can slide over each other (making graphite slippery) and a sea of delocalised electrons that allows it to conduct electricity.
共价键涉及非金属原子之间共用一对或几对电子。具有简单分子结构的物质，如水、二氧化碳和甲烷，其分子间作用力较弱，因此熔点和沸点较低。它们不能导电，因为体系中没有自由移动的带电粒子。金刚石、石墨和二氧化硅这类巨型共价结构具有极高的熔点。金刚石中每个碳原子与周围四个碳原子以四面体结构键合，因此极其坚硬且不导电。石墨中每个碳原子只与另外三个碳原子键合，形成可滑移的层状结构（因此石墨具有滑腻感），同时还有一层离域电子“海洋”，使石墨能够导电。
Metallic bonding is the electrostatic attraction between a lattice of positive metal ions and a sea of delocalised electrons. This structure explains why metals are good conductors of heat and electricity, are malleable (layers of ions can slide without breaking the metallic bonding) and ductile.
金属键是金属阳离子晶格与“离域电子海洋”之间的静电引力。这一结构解释了金属为什么是优良的导热体和导电体，为什么具有延展性（离子层可以滑动而不会破坏金属键）以及可塑性。
3. Chemical Formulae, Equations and Quantitative Chemistry | 化学式、化学方程式与定量化学
Chemical formulae are written using symbols and subscripts to show the number of each type of atom. Valency rules help you deduce the correct formula for an ionic compound, e.g. aluminium oxide is Al₂O₃ because Al³⁺ and O²⁻ combine in a ratio that balances the charges. You must be able to write word equations and balanced symbol equations for reactions covered in the specification.
化学式利用元素符号和下标数字来表示各类原子的数目。化合价规则有助于你推导离子化合物的正确化学式，例如氧化铝的化学式为Al₂O₃，因为Al³⁺和O²⁻需要以2:3的比例结合才能平衡电荷。你必须能够为大纲涉及的反应书写文字方程式和配平的符号方程式。
Relative formula mass (Mᵣ) is the sum of the relative atomic masses of all the atoms in a formula unit. The mole is the unit for amount of substance; one mole of any substance contains 6.02 × 10²³ particles and has a mass equal to its Mᵣ in grams. The key relationship is:
相对式量（Mᵣ）就是一个式单元中所有原子的相对原子质量之和。摩尔是“物质的量”的单位；1摩尔任何物质都含有6.02 × 10²³个微粒，其质量以克为单位时等于该物质的式量。核心关系为：
mass (g) = moles × Mᵣ
From this, you can calculate the mass of a product that can be produced from a given mass of reactant (reacting mass calculations), work out the percentage by mass of an element in a compound, and determine an empirical formula from experimental data. The molecular formula is a multiple of the empirical formula.
由此，你可以计算给定质量的反应物能生成多少质量产物（反应物质量计算），求算元素在化合物中的质量百分数，以及根据实验数据确定最简式。分子式是最简式的整数倍。
Concentration of a solution is commonly expressed in grams per cubic decimetre (g/dm³). Titration calculations that combine concentration and reacting mass ideas are frequently examined; the equation moles = concentration × volume (in dm³) is essential. Percentage yield and atom economy (if taught) provide further measures of reaction efficiency.
溶液的浓度通常以克每立方分米（g/dm³）来表示。滴定计算结合了浓度和反应物质量的概念，是常见考点；等式 物质的量 = 浓度 × 体积（以dm³计）至关重要。产率和原子经济性（如已学过）为衡量反应效率提供了更多手段。
4. Acids, Bases and Salts | 酸、碱和盐
Acids are substances that release H⁺ ions in aqueous solution; alkalis release OH⁻ ions. The pH scale (0 to 14) measures the acidity or alkalinity of a solution: pH less than 7 is acidic, pH 7 is neutral, and pH greater than 7 is alkaline. Universal indicator and other indicators such as litmus and phenolphthalein show characteristic colours at different pH values.
酸是在水溶液中释放H⁺离子的物质；碱释放OH⁻离子。pH标度（0–14）用于衡量溶液的酸碱度：pH小于7为酸性，pH＝7为中性，pH大于7为碱性。通用指示剂以及石蕊、酚酞等指示剂在不同pH值下会显示出特征颜色。
Neutralisation is a reaction between an acid and a base that produces a salt and water. The general word equation is: acid + base → salt + water. In IGCSE, you often meet reactions of acids with metals, metal oxides, metal hydroxides and metal carbonates. You must be able to name the salt formed: for hydrochloric acid, the salt is a chloride; for sulfuric acid, a sulfate; for nitric acid, a nitrate.
中和反应是酸与碱反应生成盐和水的过程。通用的文字方程式为：酸 + 碱 → 盐 + 水。在IGCSE中，你常常会遇到酸与活泼金属、金属氧化物、金属氢氧化物和金属碳酸盐的反应。你必须能够正确地命名生成的盐：盐酸生成的盐是氯化物；硫酸生成的盐是硫酸盐；硝酸生成的盐是硝酸盐。
There are two main ways to prepare a pure, dry sample of a salt in the laboratory:
在实验室中制备纯净、干燥的盐样品主要有两种方法：
- Soluble salts: React an acid with an excess of the metal, metal oxide or metal carbonate, then filter, evaporate and dry. If the acid and the other reactant are both soluble, titration followed by crystallisation is used to avoid excess reactant issues.
- Insoluble salts: These are prepared by precipitation – mixing two solutions each containing one of the required ions; the insoluble salt forms as a precipitate, which is then filtered, washed and dried.
- 可溶性盐：将过量的金属、金属氧化物或金属碳酸盐与酸反应，然后过滤、蒸发和干燥。如果酸和另一种反应物都是可溶的，可采用先滴定再结晶的方法，以避免反应物过量的问题。
- 难溶性盐：通过沉淀法制备——混合两种分别含有目标离子的溶液；不溶性盐以沉淀形式析出，然后过滤、洗涤并干燥。
5. Electrolysis and Its Applications | 电解及其应用
Electrolysis is the splitting up of an ionic compound using direct electric current. The electrolyte (the molten or dissolved ionic compound) conducts electricity because its ions are free to move. Positive ions (cations) migrate to the negative electrode (cathode) and are reduced; negative ions (anions) migrate to the positive electrode (anode) and are oxidised. Remember that reduction happens at the cathode and oxidation at the anode (OIL RIG).
电解是利用直流电将离子化合物分解的过程。电解质（熔融或溶解的离子化合物）因其离子可以自由移动而能导电。阳离子移向负极（阴极）并在那里发生还原反应；阴离子移向正极（阳极）并发生氧化反应。记住还原反应发生在阴极，氧化反应发生在阳极。
During the electrolysis of a molten binary compound such as lead(II) bromide, the products are straightforward: lead metal at the cathode and bromine at the anode. Electrolysis of aqueous solutions is more complex because water can also be oxidised or reduced. To predict the products at each electrode, you consider the reactivity series: at the cathode, hydrogen is produced if the metal is more reactive than hydrogen; otherwise the metal is deposited. At the anode, you compare the halide ion (if present) with hydroxide ions – a concentrated halide solution gives the halogen, otherwise oxygen is produced from water.
电解熔融的二元化合物（如溴化铅）时，产物非常直观：阴极得到金属铅，阳极得到溴。复杂的是水溶液的电解，因为水也可以被氧化或还原。要预测两极产物，你需要借助金属活动性顺序：在阴极，若金属比氢活泼，则会得到氢气；否则金属单质析出。在阳极，需要比较卤离子（如果有的话）与氢氧根离子——浓的卤化物溶液会得到卤素单质，否则水放电生成氧气。
Key applications of electrolysis include the extraction of aluminium from molten aluminium oxide dissolved in cryolite, electroplating (coating a cheaper metal with a thin layer of a more attractive or corrosion‑resistant metal), and the purification of copper. In each case, you should be able to write the half‑equations for the electrode reactions using the correct number of electrons, e.g. at the cathode in copper purification: Cu²⁺ + 2e⁻ → Cu.
电解的主要应用包括：从溶在冰晶石中的熔融氧化铝里提取金属铝；电镀（在较廉价的金属表面镀上一层更美观或更耐腐蚀的金属薄层）；以及铜的精炼。对于每一种情况，你都应能正确书写电极反应的半方程式，并配以正确的电子数目，例如在精炼铜的阴极：Cu²⁺ + 2e⁻ → Cu。
6. Energy Changes and Rate of Reaction | 能量变化与反应速率
Chemical reactions are accompanied by energy changes. In an exothermic reaction, energy is transferred to the surroundings, causing the temperature to rise. In an endothermic reaction, energy is absorbed from the surroundings and the temperature falls. Energy profile diagrams show the relative energies of reactants and products, as well as the activation energy (Eₐ), which is the minimum energy colliding particles need for a reaction to occur.
化学反应常伴随着能量变化。在放热反应中，能量被释放到周围环境中，温度升高。在吸热反应中，能量从周围环境中被吸收，温度下降。能级图（反应曲线图）不仅展示了反应物和产物的相对能量，还标识出活化能（Eₐ）——这是碰撞粒子发生反应所需的最低能量。
The overall energy change of a reaction can be linked to bond energies: energy must be supplied to break bonds (endothermic), and energy is released when new bonds form (exothermic). For simple molecules, the ΔH of a reaction can be estimated as:
反应的总能量变化与键能密切相关：断裂化学键需要吸收能量（吸热），形成新化学键则释放能量（放热）。对于简单分子，反应的ΔH可以按下式估算：
ΔH = total energy of bonds broken – total energy of bonds formed
A negative ΔH indicates an exothermic reaction; a positive ΔH indicates an endothermic reaction.
负的ΔH表示放热反应；正的ΔH表示吸热反应。
The rate of a reaction can be followed by measuring the speed of formation of a product or the speed of consumption of a reactant. According to collision theory, for a reaction to occur, particles must collide with sufficient energy (at least the activation energy) and with the correct orientation. Factors that increase the frequency or energy of collisions will increase the rate:
反应速率可以通过测定产物生成或反应物消耗的快慢来监测。根据碰撞理论，要发生反应，微粒之间必须以不低于活化能的能量并以合适的取向发生碰撞。凡是能使碰撞频率升高或每次碰撞能量增大的因素，都会提高反应速率：
- Increasing concentration (or pressure for gases) – more particles per unit volume → more frequent collisions.
- Increasing temperature – particles move faster and have more energy → more frequent collisions and a higher proportion of collisions exceeding Eₐ.
- Increasing surface area of a solid reactant – more particles exposed to react → more frequent collisions.
- Using a catalyst – provides an alternative pathway with lower activation energy.
- 增大浓度（或气体压强）——单位体积内微粒数增加 → 碰撞更频繁。
- 升高温度——微粒运动加快、能量增大 → 碰撞更频繁，且高于活化能的碰撞比例升高。
- 增大固体反应物的表面积——更多的微粒暴露在外可参与反应 → 碰撞更频繁。
- 使用催化剂——提供了活化能较低的另一条反应路径。
7. Organic Chemistry | 有机化学
Organic chemistry is the study of compounds containing carbon, often in homologous series – families of compounds with the same general formula, similar chemical properties and a trend in physical properties. In the WJEC IGCSE specification, you need to know four homologous series: alkanes, alkenes, alcohols, and carboxylic acids.
有机化学研究的是含碳化合物，它们常常组成同系列——具有相同通式、相似化学性质以及物理性质递变规律的一类化合物。在WJEC IGCSE大纲中，你需要掌握四个同系列：烷烃、烯烃、醇和羧酸。
Alkanes are saturated hydrocarbons with the general formula CₙH₂ₙ₊₂. They are characterised by single covalent bonds (C–C) and are fairly unreactive, though they will burn in plenty of oxygen to form carbon dioxide and water (complete combustion), or form carbon monoxide in limited oxygen. They also undergo substitution reactions with halogens in the presence of UV light.
烷烃是饱和烃，通式为CₙH₂ₙ₊₂。其特征是存在碳‑碳单键（C–C），化学性质相对稳定，但它们在充足的氧气中会燃烧生成二氧化碳和水（完全燃烧），氧气不足时则会有一氧化碳生成。在紫外光作用下，烷烃还能与卤素发生取代反应。
Alkenes are unsaturated hydrocarbons with the general formula CₙH₂ₙ and contain at least one carbon‑carbon double bond (C=C). This double bond makes them much more reactive than alkanes. Alkenes decolourise bromine water (an important test for unsaturation) through an addition reaction. They also undergo addition polymerisation, in which many small monomer molecules join together to form a long‑chain polymer, such as poly(ethene). You should be able to name the monomer from the repeating unit of the polymer, and vice versa.
烯烃是不饱和烃，通式为CₙH₂ₙ，分子中至少含有一个碳‑碳双键（C=C）。正是这个双键使得烯烃远比烷烃活泼。烯烃可通过加成反应使溴水褪色（检验不饱和键的重要方法）。它们还能发生加聚反应，大量小分子单体连接成长链聚合物，例如聚乙烯。你应该能够从聚合物的重复单元推断出单体名称，反之亦然。
Alcohols contain the –OH functional group. Ethanol (C₂H₅OH) is the most commonly examined alcohol. It can be produced by fermentation of glucose using yeast, or by the hydration of ethene using steam and a catalyst. Ethanol burns with a clean flame and can be oxidised to ethanoic acid (a carboxylic acid) by heating with an oxidising agent. Carboxylic acids, such as ethanoic acid, are weak acids that react with metals, carbonates, and alkalis in typical acid‑type reactions. They also react with alcohols to form esters, although ester formation is a more advanced topic and may be mentioned only as an extension.
醇含有–OH官能团。乙醇（C₂H₅OH）是考试中最常见的醇。它可以通过酵母发酵葡萄糖制得，也可用乙烯在催化剂存在下与水加成来生产。乙醇燃烧时火焰洁净，它能被氧化剂加热氧化成乙酸（一种羧酸）。羧酸如乙酸属于弱酸，能与金属、碳酸盐和碱发生典型的酸类反应。它们还能与醇反应生成酯，不过酯化反应是稍深入的内容，可能仅作拓展提及。
8. Chemical Analysis and the Environment | 化学分析与环境化学
Identifying substances and monitoring environmental impact are vital chemical skills. You must know the tests for common gases: hydrogen (burns with a squeaky pop), oxygen (relights a glowing splint), carbon dioxide (turns limewater milky), chlorine (bleaches damp litmus paper) and ammonia (turns damp red litmus paper blue).
物质的鉴别与环境影响的监测是化学中至关重要的技能。你必须牢记常见气体的检验方法：氢气（燃烧发出“噗”的一声）、氧气（使带火星的木条复燃）、二氧化碳（使石灰水变浑浊）、氯气（使湿润的蓝石蕊试纸变白后变红）以及氨气（使湿润的红色石蕊试纸变蓝）。
Flame tests distinguish many metal cations by the characteristic colour they impart to a Bunsen flame: Li⁺ gives red, Na⁺ gives intense yellow, K⁺ gives lilac, Ca²⁺ gives orange‑red, and Cu²⁺ gives green‑blue. Precipitate tests using sodium hydroxide solution also help identify metal ions such as Cu²⁺ (blue precipitate), Fe²⁺ (green), Fe³⁺ (orange‑brown) and others.
焰色反应可根据金属阳离子在本生灯火焰中显示的特征颜色进行鉴别：Li⁺为红色，Na⁺为强烈黄色，K⁺为淡紫色，Ca²⁺为砖红色，Cu²⁺为蓝绿色。利用氢氧化钠溶液进行沉淀反应进一步帮助分辨Cu²⁺（蓝色沉淀）、Fe²⁺（绿色）、Fe³⁺（橙棕色）等离子。
Tests for anions are equally important: carbonate ions react with dilute acid to form carbon dioxide; sulfate ions form a white precipitate with barium chloride solution acidified with dilute hydrochloric acid; halide ions (chloride, bromide, iodide) give precipitates of different colours with silver nitrate solution acidified with nitric acid – white for chloride, cream for bromide, yellow for iodide. Chromatography can be used to separate and identify components of a mixture based on their differing solubilities.
阴离子的检验同样重要：碳酸根离子与稀酸反应生成能使石灰水变浑浊的二氧化碳；硫酸根离子在稀盐酸酸化的条件下与氯化钡溶液生成白色沉淀；卤素离子（氯离子、溴离子、碘离子）在稀硝酸酸化的条件下与硝酸银反应，分别生成白色（氯化银）、奶油色（溴化银）和黄色（碘化银）沉淀。纸色谱法可以根据各组分在溶剂中溶解度的差异对混合物进行分离鉴别。
Chemistry also helps us understand environmental problems. Burning fossil fuels releases carbon dioxide (a greenhouse gas), sulfur dioxide and nitrogen oxides (which cause acid rain), and particulates. You should be able to describe how acid rain damages buildings and ecosystems, and how catalytic converters reduce harmful emissions from vehicles. Water purification strategies and the importance of air quality monitoring are also part of your IGCSE course.
化学还可以帮我们理解当下的环境问题。化石燃料的燃烧会释放二氧化碳（一种温室气体）、二氧化硫和氮氧化物（形成酸雨）以及颗粒物。你应当能描述酸雨如何侵蚀建筑物和破坏生态系统，以及催化转化器如何减少汽车的有害排放。水净化策略与空气质量监测的重要性同样是IGCSE课程的一部分。
Published by TutorHao
更多咨询请联系16621398022（同微信）
屏轩国际教育cambridge primary/secondary checkpoint, cat4, ukiset,ukcat,igcse,alevel,PAT,STEP,MAT, ibdp,ap,ssat,sat,sat2课程辅导，国外大学本科硕士研究生博士课程论文辅导