"元素"和"单质"的英文意思都是

"元素"和"单质"的英文意思都是 CHEMISTRY CHEMISTRY Revision guide Revision guide for IGCSE for IGCSE Written by Shane Sun For 2009 – 2010 examinations Preparing for IGCSE chemistry For 2009 – 2010 examinations Introduction CONTENTS CONTENTS CONTENTS For 2009 – 2010 examinations Preparing for IGCSE chemistry Preparing for IGCSE chemistry Section 1 Naming inorganic compounds Naming elements “元素”和“单质”的英文意思都是 “element”,有时为了区别，在强调“单质”时可用“free element”。因此，单质和元素的英文名称是一样的，下面给出的既是元素的名称，同时又是单质的名称。 1 主族元素和单质 ?A ?A ?A ?A ?A ?A ?A 0 Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulphur Chlorine Argon Potassium Calcium Gallium Gemanium Arsenic Selenium Bromine Krypton Rubidium Strontium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Thallium Lead Bismuth Polonium Astatine Radon Francium Radium 2 过渡元素和单质 Fe: Iron Mn: Manganese Zn: Zinc Hg: Mercury Ag:Silver Au: Gold Cu: Copper Naming compounds 化合物的命名顺序都是根据化学式从左到右读，这与中文读法顺序是相反的。表示原子个数时使用前缀: mono- di- tri- tetra- penta- hexa- hepta- octa- nona- deca- 一 二 三 四 五 六 七 八 九 十 1 化合物正电荷部分的读法 直呼其名，即读其元素名称 如:CO carbon monoxide AlO alminium oxide 23 NO dinitrogen tetroxide 24 对于有变价的金属元素,更多的采用罗马数字来表示金属的氧化态。 如:FeO: iron(?) oxide FeO: iron(?) oxide 23 CuO: copper(?) oxide CuO: copper(?) oxide 2 Tips: 非金属化合物用前缀表示原子个数，金属化合物不需要用前缀，只须用罗马数字标出就有多种价态 的金属元素的化合价。 E.g. Naming the compounds below: 1 Preparing for IGCSE chemistry For 2009 – 2010 examinations MnO manganese(IV) oxide CrO chromium(III) oxide 223 FeCl iron(III) chloride CuS copper(II) sulphide 3 SO sulphur trioxide NO dinitrogen pentoxide 325 FeO iron(III) oxide FeO iron(II) oxide 23 2.化合物负电荷部分的读法: 2.1 二元化合物 常见的二元化合物有卤化物、氧化物、硫化物、氮化物、磷化物、碳化物、金属氢化物等，命名是需要使用后缀,ide. 如:fluoride, chloride, bromide, iodide, oxide, sulphide, nitride, phosphide, carbide,hydride; ,OH的名称也使用后缀,ide hydroxide. 非金属氢化物不用此后缀，而是将其看成其他二元化合物(见2.2);非最低价的二元化 ,,2合物还要加前缀，如O: peroxide O:superoxide 22 例如:NaF sodium fluoride AlCl aluminium chloride MgN magnesium nitride 323 AgS silver sulphide 2 E.g. Naming the compounds below: ZnS zinc sulphide ZnO zinc oxide ZnCl zinc chloride 2 NaH sodium hydride CO carbon dioxide KOH potassium hydroxide 2 CaF calcium fluoride NaBr sodium bromide CaP calcium phosphide 232 NaO sodium peroxide HO hydrogen peroxide 2222 2.2 非金属氢化物 除了水和氨气使用俗称water，ammonia以外，其他的非金属氢化物都用系统命名，命名规则根据化学式的写法不同而有所不同。对于卤族和氧族氢化物，H在化学式中写在前面，因此将其看成另一元素的二元化合物。 例如:HF hydrogen fluoride HCl hydrogen chloride HS hydrogen sulphide 2 对于其他族的非金属氢化物，H在化学式中写在后面，可以加后缀,ane，氮族还可加,ine 例如: PH phosphine 或phosphane BH diborane 326 2.3 无氧酸 命名规则:hydro,词根,ic acid 例如:HCl hydrochloric acid HS hydrosulphuric acid 2 E.g. Naming the compounds below: HBr hydrobromic acid HI hydroiodic acid HF hydrofluoric acid 2 For 2009 – 2010 examinations Preparing for IGCSE chemistry 2.4 含氧酸 命名规则:中心原子词根(罗马数字表示化合价) , ic acid 例如:HSO sulphuric(VI) acid 24 HSO sulphuric(IV) acid 23 Tips: 若中心原子的化合价没有表示出来，则默认该酸为其正酸或原酸。例如，sulphuric acid 就是指硫酸。 E.g. Naming the compounds below: HClO chloric(VII) acid HClO chloric(V) acid or chloric acid 43HSO sulphric(IV) acid HClO chloric(I) acid 23 HNO nitric(V) acid or nitric acid HNO nitric(III) acid 32HPO phosphoric(V) acid or phosphoric acid 34 2.5 盐 2.5.1 含氧酸根的命名 命名规则:在含氧酸的基础上去掉 ,ic acid ， 加上,ate ,2例如:SO sulphate(VI) ion 4 , 2 SO sulphate(IV) ion 3 Tips: 若中心原子的化合价没有表示出来，则默认该酸根为其正酸根。例如，sulphate 就是指硫酸根, nitrate 就是指硝酸根。 而亚酸根也可以按以下规则来命名: 在含氧酸的基础上去掉 ,ic acid ， 加上,ite。例如: ,2 SO 可以命名为:sulphite 3 2.5.2 正盐: 根据化学式从左往右分别读出阳离子和阴离子的名称 E.g. Naming the compounds below: FeSO iron(II) sulphate(VI) or iron(II) sulphate FeS iron(II) sulphide 4 FeSO iron(II) sulphate(IV) or iron(II) sulphite NaCO sodium carbonate 323KNO potassium nitrate(V) or potassium nitrate KMnO potassium manganate(VII) 34KNO potassium nitrate(III) or potassium nitrite KClO potassium chlorate(I) 2 KClO potassium chlorate(V) or potassium chlorate3 2.5.3 酸式盐:同正盐的读法，酸根中的H读作hydrogen。 例如NaHCO sodium hydrogencarbonate 3 2.5.4水合盐:结晶水读作water 或 hydrate 例如: CuSO ?5HO copper(II) sulphate – 5 – water 42 3 Unit 1 BONDING AND STRUCTURE For 2009 – 2010 examinations Unit 1 BONDING AND STRUCTURE Section 1 States of matters Learning objectives: (Please note: (S) denotes material in the Supplement (Extended syllabus) only) 1 Describe the states of matter and explain their interconversion in terms of the kinetic particle theory. 2 Describe and explain diffusion. 3 Describe evidence for the movement of particles in gases and liquids. A treatment of Brownian Motion is not required 4(s) Describe dependence of rate of diffusion on molecular mass (treated qualitatively) Key words: particle 微粒 freezing 凝固 kinetic particle theory 分子运动理论 melting 熔化 volume 体积 evaporating 蒸发 vibrate 振动 boiling 沸腾 motion 运动 subliming 升华/凝华 condensing 液化 diffusion 扩散 Key ideas Arrangement and movement of the particles in each of the three states Solids Liquids Gases Shape Have a fixed shape Have no fixed shape Have no fixed shape Volume Have a definite volume Have a definite volume Have no definite volume Density Have a high density Are usually lower dense Have a very low than solids density Ability to flow Can not flow Cannot flow quite easily Can flow very easily Ability to Cannot be squashed Can be slightly squashed Quite easy to be squashed squashed Closeness of Closed one by one Have a little gap Far from each other particles between two particles Diagrams of arrangement Arrangement Regular Irregular Irregular 4 For 2009 – 2010 examinations Unit 1 BONDING AND STRUCTURE Attractive Very strong Strong No force forces between particles Movement of Vibrate at fixed Move around each other Move freely particles positions Examples Iron Water Oxygen Changes of state Changes of state are linked to changes in the motion and arrangement of particles. Diffusion 1 Definition: liquids or gases spread out in an available space. It?s an evidence for moving particles. 2 Factors influencing the speed of diffusion 1) Explanation by the kinetic particle theory Speeds of particles moving The speed of diffusion depends on Distance between particles 5 Unit 1 BONDING AND STRUCTURE For 2009 – 2010 examinations 2) Factors and explanations Factors Effect Explanations speeds of particles distance between moving particles State Gases diffuse fastest Particles in gases move Particles in gases are far fastest. from each other. Liquids diffuse fast In liquids particles move In liquids there are small but more slower than fast but more slower than gaps between these gases in gases. particles. In solids these particles In solids these particles Solids can not diffuse can only vibrate at fixed are close to each other. ( very slightly ) positions. Temperature High temperature Particles move faster in Substances expand by favours high speed high temperatures. increasing temperatures. of diffusion This is because distances between particles become more large in high temperatures. The relative The gas which has a Particles in a gas with a molecular lower Mr diffuses lower Mr moves faster. masses of faster. gases Questions 6 For 2009 – 2010 examinations Unit 1 BONDING AND STRUCTURE Section 2 Atomic structure Learning objectives 1 State the relative charges and approximate relative masses of protons, neutrons and electrons. 2 Define proton number and nucleon number. 3 Use proton number and the simple structure of atoms to explain the basis of the Periodic table (see syllabus section 9), with special reference to the elements of proton number 1 to 20. 4 Define isotopes. 5 State the two types of isotopes as being radioactive and non-radioactive. 6 State one medical and one industrial use of radioactive isotopes. 2357 Describe radioactive isotopes, such as U as a source of energy. 8 Describe the build-up of electrons in „shells? and understand the significance of the noble gas electronic structures and of valency electrons. Key words: proton 质子 isotopes 同位素 electron 电子 radioactive 放射性的 neutron 中子 noble gas 稀有气体 nucleus 原子核 valency electrons 价电子 Periodic Table 元素周期表 Key ideas: Atomic structure (protons and neutrons) Relative charge Relative mass Proton +1 1 Neutron 0 1 Electron - 1 1/1840 7 Unit 1 BONDING AND STRUCTURE For 2009 – 2010 examinations In an atom: proton number (Z) = numbers of electrons = numbers of protons nucleon number (A) = proton number + neutron number = Mr Isotopes 1 Definition: atoms of the same element ( same proton number ) which have different numbers of neutrons 2 Examples 1233537235238H H H Cl Cl U U 3 Uses of radioactive isotopes 2351) power stations (as a source of energy , such as U) 2) treat cancer Electronic configurations 1 Shells The electrons are found at considerable distances from the nucleus in a series of levels called energy levels or shells. Each energy level can only hold a certain number of electrons. Shells are numbered 1, 2, 3, 4, 5, 6, 7. These numbers are know as principal quantum numbers (symbol n) quantum numbers (n) the number of electrons can be holded 1 2 2 8 3 18 4 32 But the outer shells can only hold 8 electrons at most. 2 Atomic structural diagrams 1835O Cl 17P18N 8P10N Tips: When you draw these diagrams, you should write out the proton number and neutron number clearly. Because each element has several isotopes. 8 For 2009 – 2010 examinations Unit 1 BONDING AND STRUCTURE Questions 9 Unit 1 BONDING AND STRUCTURE For 2009 – 2010 examinations Section 3 Chemical bonding Learning objectives 1 Describe the differences between elements, mixtures and compounds, and between metals and non-metals. 2 Describe alloys, such as brass, as a mixture of a metal with other elements. 3 Identify representations of alloys from diagrams of their structures. 4 Describe bond breaking as endothermic and bond forming as exothermic. 5 Describe the formation of ions by electrons loss or gain. 6 Describe the formation of ionic bonds between elements from Groups I and VII. 7 Describe the formation of ionic bonds between metallic and non-metallic elements. 8 Describe the lattice structure of ionic compounds as a regular arrangement of alternating positive and negative ions. 9 Describe the formation of single covalent bonds in H, Cl, HO, CHand HCl as the 2224 sharing of pairs of electrons leading to the noble gas configuration. 10 Describe the electron arrangement in more complex covalent molecules such as N, 2 CH, CHOH and CO 2432. 11 Describe the differences in volatility, solubility and electrical conductivity between ionic and covalent compounds. 12 Describe the giant covalent structures of graphite and diamond. 13 Relate their structures to the use of graphite as a lubricant and of diamond in cutting. 14 Describe the macromolecular structure of silicon(IV) oxide (silicon dioxide). 15 Describe the similarity in properties between diamond and silicon(IV) oxide , related to their structures. 16 Describe metallic bonding as a lattice of positive ions in a „sea of electrons? and use this to describe the electrical conductivity and malleability of metals. Key words element 元素/单质 compound 化合物 mixture 化合物 metallic bond 金属键 alloy 合金 lattice 晶格 delocalised 电离出的 chemical bonding 化学键 ionic bond 离子键 ion 离子 cation 阳离子 anion 阴离子 covalent bond 共价键 sharing electrons 共用电子 10 For 2009 – 2010 examinations Unit 1 BONDING AND STRUCTURE tetrahedral 正四面体的 malleability 展性 ductility 延性 lubricant 润滑剂/润滑的 Key ideas Distingwish of substances 1 Relationship between all the kinds of substances in the world metal mixture element substance non - metal pure substance ionic compound compound covalent compound 2 Definitions of element , compound and mixture 1) Element – a substance which is made up of only one kind of atom. 1214i.e. O , C , C , C 260 Tips: „element? 既有‘元素’的意思，又有‘单质’的意思。 2) Compound – substances which are formed when two or more elements chemically combine together. 3) Mixture – contains more than one substance ( elements and / or compounds ). Chemical bonding Substances are made up of atoms , ions or molecules. There must be some forces between these particles to hold them on. The forces between these particles are called chemical bonds or chemical bonding. There are four kinds of chemcal bonds in all the substances. 11 Unit 1 BONDING AND STRUCTURE For 2009 – 2010 examinations Forces between atoms Covalent bonding Forces between anions and Ionic bonding cations CHEMICAL BONDING Forces between anions and Metallic bonding free electrons Intermolecular forces Forces between molecules Metallic bonds 1 Common properties of metals: good conductors of electricity good conductors of heat malleable and ductile shiny and silvery tips: malleable means that metals can be hammered into different shapes ( 展性 ) ductile means that metals can be pulled out into thin wires ( 延性 ) 2 What is a metallic bond Metallic bonding is a lattice of positive ions surrounded by mobile electrons It is a force between positive ions and free electrons. Free electrons Metal ions Metallic bonds are in Metals and alloys. 3 Properties and structures of metals 1) Why metals are malleable and ductile? This is because of the ability of the atoms to roll over each other into new positions without breaking the metallic bond. 2) Why metals are good conductors of electricity? The delocalised electrons are free to move throughout the structure 12 For 2009 – 2010 examinations Unit 1 BONDING AND STRUCTURE 3) Why metals are good conductors of heat? Heat energy is picked up by the electrons as additional kinetic energy (it makes them move faster). The energy is transferred throughout the rest of the metal by the moving electrons. 4 Alloys An alloy is a mixture of a metal with another element, usually another metal. free electron another element typical structure of an alloy Ionic bonds - + electrostatic forces Some compounds are made up of cations and anions. There are electrostatic forces between these ions. We call this kind forces ionic bonds. Tips: A cation means the ion carrying positive charge. And an anion means the ion carrying negative charge. 13 Unit 1 BONDING AND STRUCTURE For 2009 – 2010 examinations 1 Formation of ions An atom is tend to form a noble gas electronic configuration. Because it is a very stable structure. So atoms form the ions which have the same electronic configurations as noble gases by losing or gaining electrons. i.e. A sodium atom has only one outer shell electron. So it is easy to lose this outer electron to form a cation, which has the same structure as neon. But a chlorine atom has seven outer shell electrons. It is easier to gain an electron to form an anion, which has the same structure as argon. Tips : How to determine the structure of an ion? The structure of an ion is basic on the number of the outer shell electrons of the atom. And the number of the outer shell electrons of an atom equals the Group number of this atom in the Periodic table. So that we can predict the structure of an ion by the position of this element in Periodic table. Group I Group Group Group Group Group Group Group II III IV V VI VII 0 Number of the 1 2 3 4 5 6 7 0 outer shell electrons Formula easy to easy to easy to Difficult easy to easy to easy to Noble of the lose 1 lose 2 lose 3 to form gain 3 lose 1 lose 1 gases ions electron electron electron ions electron electron electron +2+3+3-2-- M M M M M M 14 For 2009 – 2010 examinations Unit 1 BONDING AND STRUCTURE 2 Ionic compound The compounds which are made up of cations and anions are called Ionic compound. 1) „Dot? and „cross? diagrams of ionic compouns i.e. 2 2++ ClONaMg NaClMgO ? electron from chlorine atom ? electron from oxygen atom × electron from sodium atom × electron from magnesium atom Alternatively, a simpler type of diagram can be used that only shows the valency electrons. 2 2++OClMgNa NaClMgO Tips: Although both representations are correct, the simpler type of diagram shown above is preferred at IGCSE. And when you draw the diagram of an anion, you should not lost the relative charge of the anion. 2) Characters of ionic compound Particles in the compound: Cations and anions. (Can not find small molecules in the compound) Forces between particles: Ionic bonding (electrostatic force) Conduct electricity in its molten state and aqueous. But can not conduct electricity in its solid state. Have high melting/boiling points for the strong ionic bonds 3) How many compounds do belong to the ionic compound? 15 Unit 1 BONDING AND STRUCTURE For 2009 – 2010 examinations • All the salts except AlCl 3 • Metal oxides • Hydroxides 4) Ionic lattice The lattice structure in a crystal of an ionic compund, such as sodium chloride, is a regular three – dimensional arrangement of alternating positive and negative ions. It is held together by strong electrostatic forces ( ionic bonds). There is no molecules, just ions. Covalent bonds Some subtances are made up of atoms, such as HCl, but atoms carry no charge. So that there must be something between the two atoms to hold them on. Actually these atoms are connected by the sharing electrons. covalent bonding forces forces + - + hydrogen sharing nucleus chlorine electrons nucleus Covalent bonds are forces between sharing electrons and nucleus. i.e. HCl molecule Cl H sharing electrons 16 For 2009 – 2010 examinations Unit 1 BONDING AND STRUCTURE 1 „Dot? and „cross? diagrams of covalent compounds /structures ClClClH HH ClHHCl22 OCO CO2 Tips: A covalent compound is the compound which only contains covalent bonds. Covalent compounds are made up of atoms. And these atoms are uncharged. Although atoms in a covalent compound carry positive or negative oxidation munbers , it does not mean these atoms carry positive or negative charge. Zzzzz zzzzzActually the oxidation number in a covalent compound stands for the position of the sharing pairs in this compound. For example in the HCl molecule , the sharing electrons is closer to the chlorine atom so that the chlorine atom has a negative oxidation munber , -1. Most of time we use a line „ – ? to stand for one pair of sharing electrons. i.e. H – Cl H – O – H Cl – Cl O=C=O This kind of fomula is called structural formula. It is more convenient to show the covalent structures. 2 How many substances do belong to the covalent structures? • Acids • Non - metals • Non – metal oxides • Organic compounds • All the other non – metal compounds • AlCl 3 17 Unit 1 BONDING AND STRUCTURE For 2009 – 2010 examinations 3 Covalent structures Have small molecules in the compound. Between molecules Simple molecular structure there are very weak forces called intermolecular forces. Covalent structures Contains many hundreds of thousands of atoms joined by strong Giant molecular structure covalent bonds 4 Properties of covalent compound Be made up of molecules or atoms Can not conduct electricity in any state. As simple molecular substances, they are usually gases, liquids or solids with low melting and boiling point. As giant molecular substances, they are usually solids with very high melting and boiling point, such as diamond , silicon and silicon(IV) oxide. 5 Diamond and graphite Graphite Diamond Diamond This is made of a tetrahedron of carbon atoms. A carbon atom forms covalent bonds to four others. Each outer atom then bonds to three others and so on. Eventually thousands of carbon atoms are bonded together, in a giantcovalent structure. Properties 1. It is very hard. This is because each atom is held strong in place by four covalent bonds. For the same covalent reason, it has a very high melting and boiling bonds point. 2. It cannot conduct electricity, because there are no ions or free electrons to carry the charge. Uses jewellery , drill bits and glass cutter 18 For 2009 – 2010 examinations Unit 1 BONDING AND STRUCTURE Graphite This is made of flat sheets of carbon atoms. Each carbon atom forms covalent bonds to three others. This gives hexagonal rings of carbon atoms. These join to make flat sheets that lie on top of each other, held together by intermolecular forces. Properties strong 1. It is soft and lubricant. This is because the sheets covalent of atoms can slide over each other easily. bonds 2. It is a good conductor of electricity. This is because each atom has four outer electrons, but only forms weak three bonds. The fourth electron is free to move intermolecular forces between the layers, carrying the charge. Uses lubricant , electrode and pencil 6 Other giant covalent structures 1) Silicon Silicon has the similar structure as diamond. A silicon atom forms covalent bonds to four others. It forms a tetrahedral structure. 2) Silicon(IV) oxide Silicon(IV) oxide also has the similar structure as diamond. Each silicon atom is connected to other four oxygen atoms. And each oxygen atom connects to other two silicon atoms. The ratio of silicon to oxygen is 1 to 2. So the formula of silicon(IV) oxide is SiO. It not 2 means there is one silicon atom and two oxygen atoms in a silicon(IV) oxide molecules. Because there is no silicon(IV) oxide molecule at all. Instead, silicon(IV) oxide is made up of silicon and oxygen atoms. 19 Unit 1 BONDING AND STRUCTURE For 2009 – 2010 examinations Summary Properties and Particles in Forces between Types of structures examples the structure particles Have all the common Metal ions and properties of metals Metallic Structure Metallic bonds (metallic crystals) free electrons Metals and alloys High M.P./B.P. Hard Conduct electricity in molten state Ionic bonds Cations and anions Ionic Structure and aqueous. (ionic crystals) All the ionic compounds Giant molecular structure/ Very high M.P./B.P. Very hard Do not conduct electricity in any Atoms Covalent bonds Macromolecular structure states. diamond graphite SiO Si SIC (atomic crystals) 2Covalent Structure Intermolecular Low M.P./B.P. Soft Molecules Do not conduct electricity in any forces states. Simple molecular structure The molecules are Covalent bonds exist ,in the Most of the covalent made up of atoms. molecules, between atoms. (molecular crystals) compounds & non - metals 20 For 2009 – 2010 examinations Unit 1 BONDING AND STRUCTURE Questions 21 Unit 2 PERIODIC TABLE 1 For 2009 – 2010 examinations Unit 2 PERIODIC TABLE 1 Section 1 Energy transfering in chemical reactions & Structure of Periodic Table Learning objectives: 1 Describe the meaning of exothermic and endothermic reactions. 2 Describe the Periodic Table as a method of classifying elements and its use to predict properties of elements. 3 Describe the change from metallic to non-metallic character across a Period. 4 Describe the relationship between Group number, number of valency electrons and metallic/non-metallic character. 5 Describe the general physical and chemical properties of metals. 6 Explain why metals are often used in the form of alloys. Key Words exothermic 放热的 endothermic 吸热的 Periodic Table 元素周期表 Period 周期 Group 族 valency electrons 价电子 alloy 合金 Key ideas Energy transfering in chemical reactions Endothermic reaction – the reaction Energy Product ?H Reactant ?H > 0 endothermic Some endothermic reactions: Decomposition of CaCO 3 CaCO(s) CaO(s) + CO(g) 32 Photosynthesis light 6CO(g) + 6HO(l) CHO + 6O(g) 2261262 22 For 2009 – 2010 examinations Unit 1 BONDING AND STRUCTURE Exothermic reaction – the reaction gives out energy Energy Reactant ?H Product Process ?H < 0 exothermic Some exothermic reactions: Oxidation of fuels and respiration of glucose + carbohydrates. 23