Year 9 WJEC Chemistry: Glossary and Key Terms Quick Memorisation Guide | WJEC 化学词汇术语速记指南

📚 Year 9 WJEC Chemistry: Glossary and Key Terms Quick Memorisation Guide | WJEC 化学词汇术语速记指南

Mastering the vocabulary of chemistry is essential for understanding concepts and achieving high marks in Year 9 WJEC chemistry. This guide presents key terms grouped by topic, each with a clear definition, memory tricks, and a Chinese explanation to support bilingual learners.

掌握化学词汇是理解概念并在WJEC九年级化学中取得高分的关键。本指南按主题分组列出关键术语，每个术语都配有清晰的定义、记忆技巧和中文解释，帮助双语学习者巩固。

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1. States of Matter and Particle Theory | 物质状态与粒子理论

Solid (固体): Have a fixed shape and volume; particles are tightly packed in a regular arrangement and can only vibrate. Think ‘Solid as a soldier standing still’.

固体: 具有固定的形状和体积；粒子紧密排列成规则结构，只能在原位振动。记忆联想：“固体如同纹丝不动的士兵”。

Liquid (液体): Have a fixed volume but take the shape of their container; particles are close together but can slide past each other. Imagine them as ‘a queue of people shuffling slowly’.

液体: 体积固定但形状随容器而变；粒子彼此靠近但可以相互滑动。想象“缓慢挪动的人群队列”。

Gas (气体): Have no fixed shape or volume and spread out to fill any container; particles are far apart and move quickly in all directions. They act like ‘bouncing balls in a room’.

气体: 没有固定的形状和体积，会扩散充满整个容器；粒子间距离很远，朝各个方向快速运动。好比“房间里四处弹跳的球”。

Melting (熔化) and Freezing (凝固): Melting is solid → liquid at its melting point; freezing is liquid → solid at its freezing point. They are reverse processes at the same temperature.

熔化与凝固: 熔化是固体在其熔点转变为液体；凝固是液体在其凝固点转变为固体。两者是在相同温度下的可逆过程。

Boiling (沸腾) and Condensation (冷凝): Boiling occurs throughout a liquid when its vapour pressure equals atmospheric pressure; condensation is gas → liquid on cooling. ‘Boiling bubbles throughout, condensation forms droplets’.

沸腾与冷凝: 沸腾发生在液体蒸气压等于大气压时，整个液体中都出现气泡；冷凝是气体冷却变成液体。“沸腾冒泡全面动，冷凝小滴表面逢”。

Sublimation (升华) and Diffusion (扩散): Sublimation is solid → gas skipping the liquid phase (e.g., dry ice). Diffusion is the movement of particles from an area of high concentration to low concentration.

升华与扩散: 升华是固体跳过液态直接变为气体（如干冰）。扩散是粒子从高浓度区域向低浓度区域的运动。

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2. Atoms, Elements and Compounds | 原子、元素与化合物

Atom (原子): The smallest particle of an element that can take part in a chemical reaction. Picture a tiny solar system with a nucleus and orbiting electrons.

原子: 能参与化学反应的元素最小粒子。形象化为一个极小的太阳系，原子核居中，电子绕行。

Element (元素): A substance made of only one type of atom, found on the Periodic Table. Carbon, oxygen and iron are all elements.

元素: 仅由一种原子组成的物质，周期表上的每一个格子就是一种元素。碳、氧和铁都是元素。

Compound (化合物): A substance formed when two or more different elements are chemically bonded together. Water (H₂O) is a compound of hydrogen and oxygen.

化合物: 由两种或多种不同元素以化学键结合而成的物质。水 (H₂O) 就是氢和氧的化合物。

Molecule (分子): A group of atoms bonded together, representing the smallest unit of a compound that retains its chemical properties. O₂ is a molecule of oxygen.

分子: 原子通过化学键结合在一起的集团，是保持化合物化学性质的最小单元。O₂ 是一个氧分子。

Proton, Neutron, Electron (质子、中子、电子): Proton: positive, in nucleus. Neutron: neutral, in nucleus. Electron: negative, orbits nucleus. Remember ‘Proton Positive, Neutron Neutral’.

质子、中子、电子: 质子带正电，位于原子核内；中子不带电，也位于原子核内；电子带负电，绕核运动。用首字母联想：“Proton Positive, Neutron Neutral”。

Atomic Number and Mass Number (原子序数与质量数): Atomic number = number of protons (and electrons in a neutral atom). Mass number = protons + neutrons. ‘Mass is the SUM, atomic is the IDENTITY’.

原子序数与质量数: 原子序数 = 质子数（也等于中性原子中的电子数）。质量数 = 质子数 + 中子数。“质量是总数，序数是身份”。

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3. The Periodic Table | 元素周期表

Period (周期) and Group (族): A period is a horizontal row – elements change from metals to non-metals across it. A group is a vertical column – elements have similar chemical properties.

周期与族: 周期是横行，同一周期内元素从左到右由金属渐变为非金属。族是竖列，同族元素具有相似的化学性质。

Alkali Metals (碱金属) – Group 1: Highly reactive metals (e.g., Li, Na, K) stored under oil. They react vigorously with water to form an alkali and hydrogen gas. ‘Reactivity increases down the group’.

碱金属 – 第1族: 非常活泼的金属（如锂、钠、钾），需保存在油中。它们与水剧烈反应生成碱和氢气。“反应性自上而下递增”。

Halogens (卤素) – Group 7: Reactive non-metals (e.g., F, Cl, Br, I). Fluorine is the most reactive. They form salts with metals. ‘Reactivity decreases down the group’.

卤素 – 第7族: 活泼的非金属（如氟、氯、溴、碘）。氟最活泼。它们与金属反应生成盐。“反应性自上而下递减”。

Noble Gases (惰性气体) – Group 0: Very unreactive gases (e.g., He, Ne, Ar) with a full outer electron shell. They are used in lighting and as inert atmospheres.

惰性气体 – 第0族: 极不活泼的气体（如氦、氖、氩），最外层电子已满。用于照明和保护气氛。

Metals and Non-metals (金属与非金属): Metals are typically shiny, conductive, and malleable (left side). Non-metals are dull, brittle, and poor conductors (right side). The staircase separates them.

金属与非金属: 金属通常有光泽、导电、可锻（位于左边）；非金属暗淡、脆、不导电（位于右边）。分界线呈阶梯状。

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4. Chemical Bonding Basics | 化学键入门

Ionic Bonding (离子键): Electrostatic attraction between positive and negative ions. Metals lose electrons to form cations; non-metals gain electrons to form anions. Example: Na⁺Cl⁻.

离子键: 正负离子之间的静电引力。金属失电子形成阳离子，非金属得电子形成阴离子。例如：Na⁺Cl⁻。

Covalent Bonding (共价键): Sharing of electron pairs between non-metal atoms. Each shared pair is a covalent bond. In H₂O, oxygen shares electrons with two hydrogen atoms.

共价键: 非金属原子间通过共用电子对结合。每一对共用电子就是一个共价键。水分子 H₂O 中氧与两个氢各共用一对电子。

Metallic Bonding (金属键): A lattice of positive metal ions surrounded by a sea of delocalised electrons. This explains conductivity and malleability. ‘Positive ions in a sea of electrons’.

金属键: 金属正离子规则排列，沉浸在离域电子的“海洋”中。这解释了金属的导电性和延展性。“正离子漂浮在电子海中”。

Lattice (晶格): A regular repeating 3D arrangement of particles (ions, atoms or molecules). Giant ionic lattices have high melting points due to strong bonds.

晶格: 粒子（离子、原子或分子）在三维空间规则重复排列的结构。巨型离子晶格因键合力强而熔点高。

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5. Chemical Formulas and Equations | 化学式与方程式

Chemical Formula (化学式): Shows the elements in a compound and the ratio of atoms. H₂O means 2 hydrogen atoms and 1 oxygen atom. Subscripts are tiny numbers.

化学式: 表示化合物所含元素及其原子个数比。H₂O 表示2个氢原子和1个氧原子。下标是微型数字。

Word Equation (文字方程式): Uses names of reactants and products. Example: sodium + water → sodium hydroxide + hydrogen. It shows what reacts and what forms.

文字方程式: 用物质名称表示反应物和生成物。例如：钠 + 水 → 氢氧化钠 + 氢气。它说明了什么参与反应、什么生成。

Symbol Equation (符号方程式): Uses chemical formulas. It must be balanced: number of atoms of each element same on both sides. 2H₂ + O₂ → 2H₂O.

符号方程式: 用化学式书写。必须配平：每种元素反应前后的原子总数相等。2H₂ + O₂ → 2H₂O。

State Symbols (状态符号): (s) = solid, (l) = liquid, (g) = gas, (aq) = aqueous (dissolved in water). They give information about physical state.

状态符号: (s) 固体，(l) 液体，(g) 气体，(aq) 水溶液（溶于水）。它们提供了物质的物理状态信息。

Reactants and Products (反应物与生成物): Reactants are substances that start a reaction (left of arrow). Products are new substances formed (right of arrow). ‘Reactants go in, products come out’.

反应物与生成物: 反应物是起始物质，写在箭号左边；生成物是形成的新物质，写在箭号右边。“反应物进，生成物出”。

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6. Acids, Alkalis and Neutralisation | 酸、碱与中和

Acid (酸): A substance that releases hydrogen ions (H⁺) in water. It has a pH less than 7. Common lab acids: hydrochloric acid (HCl), sulfuric acid (H₂SO₄).

酸: 溶于水时释放氢离子 (H⁺) 的物质，pH 小于7。实验室常见酸：盐酸 HCl、硫酸 H₂SO₄。

Alkali (碱) and Base (碱基): Alkalis are soluble bases that release hydroxide ions (OH⁻) in water, pH >7. All alkalis are bases, but not all bases are alkalis.

碱与碱基: 碱是溶于水能释放氢氧根离子 (OH⁻) 的可溶性碱基，pH 大于7。所有碱都是碱基，但有些碱基不溶于水不是碱。

Neutralisation (中和): The reaction between an acid and a base to form salt and water: H⁺ + OH⁻ → H₂O. The pH moves towards 7.

中和反应: 酸和碱反应生成盐和水：H⁺ + OH⁻ → H₂O。pH 趋近于7。

pH Scale (pH标度): Measures how acidic or alkaline a solution is, from 0 (strong acid) to 14 (strong alkali), with 7 neutral. Universal indicator shows a range of colours.

pH标度: 量度溶液酸碱度的标尺，0 为强酸，14 为强碱，7 为中性。通用指示剂在不同 pH 下会显示不同颜色。

Indicator (指示剂): A substance that changes colour depending on pH. Litmus turns red in acid and blue in alkali. Universal indicator gives a full colour spectrum.

指示剂: 随 pH 变化而变色的物质。石蕊在酸中变红，在碱中变蓝。通用指示剂呈现全色谱颜色变化。

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7. Chemical Reactions and Energy | 化学反应与能量

Exothermic (放热反应): A reaction that releases heat energy to the surroundings, causing a temperature rise. Combustion and neutralisation are exothermic. ‘Exo = exit heat’.

放热反应: 向周围环境释放热量、使温度升高的反应。燃烧和中和反应是放热的。“Exo 即热量外逸”。

Endothermic (吸热反应): A reaction that absorbs heat energy from the surroundings, causing a temperature drop. Photosynthesis and thermal decomposition are endothermic. ‘Endo = enter heat’.

吸热反应: 从周围环境吸收热量、使温度降低的反应。光合作用和热分解是吸热的。“Endo 即热量进入”。

Activation Energy (活化能): The minimum energy particles must have for a reaction to happen when they collide. It is the barrier that must be overcome.

活化能: 粒子发生有效碰撞所需的最低能量，是反应必须跨越的能量壁垒。

Combustion (燃烧): A rapid exothermic reaction of a substance with oxygen, producing oxides and heat/light. Complete combustion of hydrocarbons gives CO₂ + H₂O.

燃烧: 物质与氧气的快速放热反应，产生氧化物和热/光。碳氢化合物完全燃烧生成 CO₂ 和 H₂O。

Thermal Decomposition (热分解): Breaking down a compound using heat. Example: calcium carbonate → calcium oxide + carbon dioxide. It is endothermic.

热分解: 用热量将化合物分解。例如：碳酸钙 →

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