"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:
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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
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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
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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
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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
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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
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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
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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.
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For 2009 – 2010 examinations Unit 1 BONDING AND STRUCTURE
Questions
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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
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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.
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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
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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.
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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
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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?
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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
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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
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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
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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.
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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
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For 2009 – 2010 examinations Unit 1 BONDING AND STRUCTURE
Questions
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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
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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.
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