📚 Year 8 Edexcel Chemistry: Key Terms Memorisation Guide | Year 8 Edexcel 化学：词汇术语速记指南
Building a strong vocabulary is the first step towards mastering Year 8 Edexcel Chemistry. This guide breaks down the must-know terms with clear definitions and clever memory tricks. Whether you are revising for an end-of-topic test or preparing for the next level, learning the language of chemistry will make every concept easier to understand and remember.
建立扎实的词汇基础是掌握 Year 8 Edexcel 化学的第一步。这份指南用清晰的定义和巧妙的记忆技巧拆解必背术语。无论你是在为主题测验复习，还是为更高阶的学习做准备，掌握化学的语言都会让每一个概念变得更易理解和记忆。
1. Particles and the States of Matter | 粒子与物质状态
All substances are made from tiny particles that are constantly moving. The arrangement and energy of these particles decide whether a substance is a solid, a liquid or a gas. This is called the particle model.
所有物质都由不断运动的微小粒子组成。这些粒子的排列方式和能量决定了物质是固体、液体还是气体。这就是粒子模型。
Solid: Particles are tightly packed in a regular pattern and can only vibrate in fixed positions. Solids have a fixed shape and a fixed volume.
固体：粒子紧密排列成规则的结构，只能在固定位置振动。固体有固定的形状和体积。
Liquid: Particles are close together but arranged randomly; they can slide past one another. Liquids have a fixed volume but take the shape of the bottom of their container.
液体：粒子彼此靠近但排列不规则；它们可以相互滑动。液体有固定的体积，但会变成容器底部的形状。
Gas: Particles are far apart and move rapidly in all directions. Gases have no fixed shape or volume and can be compressed easily.
气体：粒子相距很远，快速向各个方向运动。气体没有固定的形状和体积，容易被压缩。
Diffusion: The movement of particles from an area of high concentration to an area of low concentration. For example, perfume spreads through a room.
扩散：粒子从高浓度区域向低浓度区域的运动。例如，香水在房间内散开。
Memory trick: Imagine students sitting neatly in an assembly (solid), walking around a classroom (liquid), and sprinting on a sports field (gas).
记忆窍门：想象学生整齐坐在礼堂里（固体），在教室里走动（液体），在运动场上奔跑（气体）。
2. Inside the Atom: Subatomic Particles | 原子内部：亚原子粒子
An atom is the smallest part of an element that can still take part in chemical reactions. The word comes from the Greek ‘atomos’ meaning indivisible.
原子是能参与化学反应的元素最小组成部分。这个词源自希腊语“atomos”，意思是不可分割。
Nucleus: The tiny, dense central part of an atom, containing protons and neutrons. Almost all the mass is here.
原子核：原子中心极小且致密的部分，包含质子和中子。几乎全部质量都集中于此。
Proton: A subatomic particle with a relative charge of +1 and a relative mass of 1. Found in the nucleus.
质子：相对电荷为+1，相对质量为1的亚原子粒子。位于原子核中。
Neutron: A subatomic particle with no charge (0) and a relative mass of 1. It sits in the nucleus alongside protons.
中子：不带电荷（0），相对质量为1的亚原子粒子。与质子一起位于原子核中。
Electron: A subatomic particle with a relative charge of -1 and a negligible mass. Electrons move around the nucleus in shells.
电子：相对电荷为-1，质量可忽略不计的亚原子粒子。电子在核外的电子层上运动。
Memory aid: Proton = Positive, Neutron = Neutral, Electron = Electric. Think ‘P for positive, N for no charge’.
记忆助手：质子带正电（Positive），中子不带电（Neutral），电子带负电（Electric）。记住“P 代表正，N 代表无电荷”。
3. Elements and the Periodic Table | 元素与周期表
An element is a pure substance made of only one type of atom. Each element has a unique symbol, such as C for carbon and O for oxygen. The periodic table lists all known elements in order of atomic number.
元素是仅由一种原子组成的纯净物。每种元素都有一个独特的符号，例如碳用 C 表示，氧用 O 表示。周期表按原子序数排列所有已知元素。
Group: A vertical column in the periodic table. Elements in the same group have similar chemical properties because they have the same number of electrons in their outer shell.
族：周期表中的纵列。同一族的元素通常具有相似的化学性质，因为它们最外层电子数相同。
Period: A horizontal row in the periodic table. As you move across a period, properties change from metallic to non-metallic.
周期：周期表中的横行。从左到右移动时，元素性质从金属性变为非金属性。
Metal: An element that is typically shiny, conducts heat and electricity, and is malleable. Examples: iron (Fe), copper (Cu).
金属：通常有光泽、能导热导电、具有延展性的元素。例如铁（Fe）、铜（Cu）。
Non-metal: An element that is usually dull, does not conduct electricity (except graphite), and is brittle when solid. Examples: sulfur (S), chlorine (Cl).
非金属：通常暗淡无光泽、不导电（石墨除外）、固态时质脆的元素。例如硫（S）、氯（Cl）。
Quick link: ‘Group = same group of outer electrons, Period = predictable pattern’.
快速联想：“族 = 相同的外层电子群，周期 = 可预测的变化模式”。
4. Compounds and Chemical Formulae | 化合物与化学式
A compound is a substance formed when two or more different elements are chemically bonded together. The properties of a compound are completely different from those of the elements that make it. For example, sodium chloride (NaCl) is made from reactive sodium metal and poisonous chlorine gas, yet it is safe table salt.
化合物是由两种或多种不同元素通过化学键结合而成的物质。化合物的性质与组成它的元素的性质完全不同。例如，氯化钠（NaCl）是由活泼的金属钠和有毒的氯气化合而成的，但它是安全的食盐。
Molecule: A group of atoms held together by covalent bonds. Some elements exist as molecules, like O₂ (oxygen gas), but a compound like H₂O is also a molecule.
分子：通过共价键结合的一组原子。某些元素以分子形式存在，如 O₂（氧气），但像 H₂O 这样的化合物也是分子。
Chemical formula: A combination of symbols and numbers that shows the types and number of atoms in the smallest unit of a substance. For example, CO₂ has one carbon atom and two oxygen atoms.
化学式：用符号和数字组合表示物质最小单元中原子种类和个数的式子。例如，CO₂ 含有 1 个碳原子和 2 个氧原子。
Subscript: The small number written slightly below the line in a formula, telling us how many atoms of the preceding element are present. In H₂O, the subscript ₂ means two hydrogen atoms.
下标：化学式中写在符号右下角的小数字，表示该元素的原子个数。在 H₂O 中，下标 ₂ 表示两个氢原子。
Memorise: ‘Compounds are chemically combined; mixtures are physically mixed.’
记住：“化合物是化学结合；混合物是物理混合。”
5. Mixtures and Pure Substances | 混合物与纯净物
A pure substance consists of only one element or one compound with fixed melting and boiling points. A mixture is made of two or more substances (elements or compounds) that are not chemically joined and can be separated by physical methods.
纯净物只含有一种元素或一种化合物，具有固定的熔点和沸点。混合物由两种或多种物质（元素或化合物）组成，它们之间没有发生化学结合，可以用物理方法分离。
Solution: A homogeneous mixture where a solute dissolves in a solvent. The particles are evenly spread and cannot be filtered out.
溶液：一种均一混合物，溶质溶解在溶剂中。粒子均匀分散，无法通过过滤分离。
Solute: The solid (or gas, liquid) that dissolves to form a solution, e.g. salt in salt water.
溶质：溶解形成溶液的固体（或气体、液体），如盐水中的盐。
Solvent: The liquid (or other phase) that does the dissolving, e.g. water in salt water.
溶剂：起溶解作用的液体（或其他相），如盐水中的水。
Suspension: A heterogeneous mixture in which solid particles are dispersed in a liquid but eventually settle out, such as sandy water.
悬浮液：一种不均匀混合物，固体颗粒分散在液体中，但最终会沉降，如含沙的水。
Clue: ‘Solute + Solvent = Solution’ – just like a simple sum.
线索：“溶质 + 溶剂 = 溶液”——就像一道简单的加法。
6. Physical and Chemical Changes | 物理变化与化学变化
A physical change alters the state or appearance of a substance but no new substance is formed. Melting, freezing, and boiling are physical changes. A chemical change produces one or more new substances, often accompanied by an energy change.
物理变化改变物质的状态或外观，但没有新物质生成。熔化、结冰和沸腾都是物理变化。化学变化则生成一种或多种新物质，并常伴随能量变化。
Reactant: A substance you start with in a chemical reaction. Reactants are written on the left-hand side of a word or symbol equation.
反应物：化学反应起始时存在的物质。反应物写在文字方程式或符号方程式的左边。
Product: A substance made during a chemical reaction. Products appear on the right-hand side of the equation.
生成物：化学反应过程中生成的物质。生成物写在方程式的右边。
Precipitate: An insoluble solid that forms when two solutions are mixed. It can be seen as cloudiness or particles sinking.
沉淀：两种溶液混合时形成的不溶性固体。可以观察到溶液变浑浊或有颗粒沉降。
Evolution of gas: Bubbles of gas produced during a reaction, often seen when a metal reacts with an acid.
气体逸出：反应过程中产生的气泡，常见于金属与酸反应时。
Remember: ‘Chemical changes make something New, physical changes are temporary Twists.’
记住：“化学变化创造新物质（New），物理变化只是暂时的形态改变（Twists）。”
7. Acids, Alkalis and Neutralisation | 酸、碱与中和反应
An acid is a substance that releases hydrogen ions (H⁺) in aqueous solution. Acids typically taste sour and turn blue litmus red. Common lab acids include hydrochloric acid (HCl) and sulfuric acid (H₂SO₄).
酸是在水溶液中能释放氢离子（H⁺）的物质。酸通常有酸味，能使蓝色石蕊试纸变红。实验室常见酸有盐酸（HCl）和硫酸（H₂SO₄）。
An alkali is a soluble base that releases hydroxide ions (OH⁻) in water. Alkalis feel soapy and turn red litmus blue. Sodium hydroxide (NaOH) is a typical alkali.
碱是可溶性的碱，在水中释放氢氧根离子（OH⁻）。碱有滑腻感，能使红色石蕊试纸变蓝。氢氧化钠（NaOH）是一种典型碱。
Neutralisation: A reaction between an acid and an alkali that produces a salt and water. The H⁺ ions from the acid combine with OH⁻ ions from the alkali to form H₂O.
中和反应：酸和碱反应生成盐和水的反应。酸中的 H⁺ 离子与碱中的 OH⁻ 离子结合生成 H₂O。
Salt: The ionic compound formed when a metal (or ammonium) replaces the hydrogen of an acid. For example, sodium chloride (NaCl) is produced from hydrochloric acid and sodium hydroxide.
盐：金属（或铵根）取代酸中的氢之后形成的离子化合物。例如，盐酸与氢氧化钠反应生成氯化钠（NaCl）。
Memory phrase: ‘Acid + Alkali → Salt + Water’ is as predictable as an equation. ‘Alkali feels slipery’ – like soap.
记忆口诀：“酸 + 碱 → 盐 + 水”像公式一样可预测。“碱摸起来滑滑的”——像肥皂一样。
8. The pH Scale and Indicators | pH 标度与指示剂
The pH scale measures how acidic or alkaline a solution is. It runs from 0 (very acidic) to 14 (very alkaline), with 7 being neutral. The scale is logarithmic, but for Year 8 you just need to compare the numbers.
pH 标度衡量溶液的酸碱程度。范围从 0（强酸性）到 14（强碱性），7 为中性。标度是对数尺度，但在 Year 8 阶段你只需比较数值。
Universal indicator: A mixture of dyes that turns a range of colours depending on the pH. It can show red-orange-yellow for acids, green for neutral, and blue-purple for alkalis.
通用指示剂：一种混合染料，根据 pH 值显示不同的颜色。酸性显示红-橙-黄色，中性显示绿色，碱性显示蓝-紫色。
Litmus: A natural indicator made from lichens. It turns red in acids and blue in alkalis, but cannot tell you the exact pH value.
石蕊：从地衣中提取的天然指示剂。遇酸变红，遇碱变蓝，但不能指示具体的 pH 值。
pH meter: An electronic instrument that gives a precise numerical pH reading. It is more accurate than indicators.
pH 计：一种电子仪器，能精确显示 pH 数值。它比指示剂更准确。
Slogan: ‘Seven is neutral heaven; below seven acid shows, above seven alkali grows.’
口号：“7 是中性天堂；低于 7 显酸性，高于 7 显碱性。”
9. Separation Techniques | 分离技术
Mixtures can be separated using physical methods that take advantage of differences in properties. Choosing the right technique depends on the type of mixture.
利用物质性质上的差异，可以通过物理方法分离混合物。选择合适的分离技术取决于混合物的类型。
Filtration: Separates an insoluble solid from a liquid using filter paper. The solid left on the paper is called the residue; the liquid that passes through is the filtrate.
过滤：用滤纸将不溶性固体与液体分离。留在滤纸上的固体叫滤渣，透过滤纸的液体叫滤液。
Evaporation: Heating a solution until the solvent boils off, leaving the solute behind. Good for obtaining a dissolved solid when the liquid is not needed.
蒸发：加热溶液直到溶剂沸腾逸出，留下溶质。适用于不保留液体的场合。
Distillation: Heating a liquid to form vapour and then condensing the vapour back into a liquid. Simple distillation separates a solvent from a solute; fractional distillation separates a mixture of miscible liquids with different boiling points.
蒸馏：将液体加热形成蒸气，再将蒸气冷凝回液体。简单蒸馏分离溶剂与溶质；分馏分离沸点不同的互溶液体混合物。
Chromatography: A technique that separates coloured substances dissolved in a solvent. Substances travel different distances on the paper, forming a chromatogram.
色谱法：一种分离溶解在溶剂中的有色物质的技术。不同物质在纸上移动的距离不同，形成色谱图。
Memory link: ‘Filter paper catches the bits; distillation boils and splits.’
记忆关联：“滤纸截留固体颗粒；蒸馏靠沸腾分离开。”
10. Energy Changes in Reactions | 反应中的能量变化
Chemical reactions always involve an energy change. Energy may be given out or taken in, usually as heat. Recognising the difference is vital for lab safety and understanding processes like combustion.
化学反应总是伴随着能量变化。能量可能以热能的形式放出或吸收。识别这些差异对实验室安全和理解燃烧等过程至关重要。
Exothermic reaction: A reaction that releases energy into the surroundings, causing a rise in temperature. Combustion (burning) and neutralisation are exothermic.
放热反应：向周围环境释放能量，导致温度升高的反应。燃烧（着火）和中和反应都是放热反应。
Endothermic reaction: A reaction that absorbs energy from the surroundings, resulting in a temperature drop. Thermal decomposition of calcium carbonate is a good example.
吸热反应：从周围环境吸收能量，导致温度降低的反应。碳酸钙的热分解就是一个典型例子。
Combustion: A rapid exothermic reaction between a substance and oxygen, producing oxides and releasing heat and light. The word equation is fuel + oxygen → carbon dioxide + water (for hydrocarbons).
燃烧：物质与氧气发生的快速放热反应，生成氧化物并释放热和光。碳氢化合物的文字方程式：燃料 + 氧气 → 二氧化碳 + 水。
Thermal decomposition: Breaking down a compound by heating it. Many carbonates decompose into a metal oxide and carbon dioxide, which is endothermic.
热分解：通过加热使一种化合物分解。许多碳酸盐分解生成金属氧化物和二氧化碳，这是吸热过程。
Quick recall: ‘Exo = Exit heat to outside; Endo = Enter, heat goes in.’
迅速回忆：“Exo = 热量 Exit（出去）；Endo = 热量 Enter（进入）。”
Published by TutorHao | Chemistry Revision Series | aleveler.com
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