Chapter 2 Matter is Made up of Atoms - My eCoach2章,物质是由原子-我开放
APES_Chapter_2_Science_Matter_Energy_and_Systems_2010-09
Science
world follow orderly cause-and-effect patterns that can be understood through careful observation, measurements, experimentation, and modeling.
Concept
2-1 Scientists collect data and develop theories, models, and laws about how nature works. – endeavor to discover how nature works and to use that knowledge to make predictions about what is likely to happen in nature.
• Studies how climate systems work, document past
climate changes, and project future changes.
The 4th IPCC report, 2007 • Very likely (90-99% probability) that the
story
• Polynesians arrived about 800 years ago
• Population may have reached 3000
• Used trees in an unsustainable manner, but rats
may have multiplied and eaten the seeds of the trees
(懂你英语)英语流利说 Level3 Unit2 Part1(完整版)
Level3.Unit2 Part1作者：Ding MingListening: States of Matter物质状态Matter is made of atoms and molecules.Water, for example, is the H2O molecule.This means that a molecule of water has 3 atoms.这意味着水分子有3个原子。
A water molecule has two hydrogen atoms and one oxygen atom.Substances like sugar have many atoms in their molecules.A molecule of sugar has many atoms, including carbon, hydrogen and oxygen.------------------------------------------------------------------------------------------------------Matter is made of molecules, such as H2O, which is the water molecule.Matter can be one of three states, solid, liquid or gas.Water and ice are the same substance, but they are in different states.These states depend on the temperature of the molecules.When we heat a substance, the molecules move faster and try to take up more space. When we cool a substance, the molecules move more slowly.When we cool a substance to its freezing point, it becomes a solid.-------------------------------------------------------------------------------------------------------------In a solid, the molecules move very little.Their positions are almost fixed.To be fixed means that their positions don’t change.If we heat the molecules, they move faster and away from each other.The solid begins to melt, like ice cream on a hot day.-----------------------------------------------------------------------------------------------------------At a certain temperature, a solid begins to change into a liquid.The temperature at which a solid change into a liquid depends on the substance.For water, the solid begins to change into a liquid when its temperature rises to about 0 degree Celsius.For some substances, such as steel, the temperature at which it becomes a liquid is much higher.对于某些物质,如钢,它变成液体的温度要高得多。
Prentice Hall Biology Chapter 2 《The Chemistry of Life》Summary
The atom is the basic unit of matter. The particles that make up atoms are protons, neutrons, and electrons.•Protons and neutrons form the nucleus,or center of the atom. Protons are positively (ϩ) charged. Neutrons have no charge. Protons and neutrons have about the same mass. •Electrons are negatively (Ϫ) charged particles.Atoms have equal numbers of electrons and protons. For this reason, atoms do not have a charge.A chemical element is a pure substance made up of only one type of atom. An element’s atomic number is the number of pro-tons in one atom of an element. Atoms of the same element can have different numbers of neutrons. These are called isotopes.All the isotopes of an element have the same number of protons and electrons. Because they have the same number of electrons, all isotopes of an element have the same chemical properties.A chemical compound is a substance formed by the joining of two or more elements in definite proportions. Chemical bonds hold the atoms in compounds together. The main types of chemical bonds are ionic bonds and covalent bonds.•An ionic bond forms when one or more electrons are transferred from one atom to another. •A covalent bond forms when electrons are shared between atoms.Atoms joined together by covalent bonds form molecules. A molecule is the smallest unit of most compounds.2–2 Properties of WaterWater molecules (H 2O) are neutral. Yet, the oxygen end of a water molecule has a slight positive charge. The hydrogen end has a slight negative charge. A molecule in which there is an uneven distribution of charges between atoms is called a polar molecule.A water molecule is polar. Polar molecules can attract one another. A hydrogen bond forms from the attraction between the hydrogen atom on one water molecule and the oxygen atom on another. Cohesion is an attraction between molecules of the same substance. Adhesion is an attraction between molecules of different substances.Summary2–1 The Nature of MatterA mixture is formed by two or more elements or compounds that are physically mixed together but not chemically joined. Salt and pepper stirred together are a mixture. Two types of mixtures that can be made with water are solutions and suspensions.•In a solution,all the components are evenly spread out. The substance dissolved in a solution is the solute.The substance in which the solute dissolves is the solvent.For example,in a salt-water solution, the salt is the solute and the wateris the solvent.•Mixtures of water and undissolved materials are suspensions.For example, if you mix sand and water, the water willbecome cloudy. However, once you stop mixing, the sandparticles will filter out and settle to the bottom. This is anexample of a suspension.A water molecule (H2O) can form a hydrogen ion (Hϩ) and ahydroxide ion (OHϪ). Chemists often measure the concentration of hydrogen ions. The pH scale indicates the concentration ofHϩions in a solution. The pH scale ranges from 0 to 14.•Pure water has a pH of 7.•An acid forms Hϩions in solution. Acidic solutions havehigher concentrations of Hϩions than pure water. Theyhave pH values below 7.•A base forms OHϪions in solution. Basic, or alkaline, solu-tions have lower concentrations of Hϩions than pure water.They have pH values above 7.2–3 Carbon CompoundsOrganic chemistry is the study of compounds with bonds between carbon atoms. Carbon compounds also are known as organic com-pounds. Many molecules in living things are very large. Very large molecules are called macromolecules. Macromolecules form through polymerization. In this process, smaller units, called monomers, join to form macromolecules, called polymers.Four groups of organic compounds found in living things are carbohydrates, lipids, nucleic acids, and proteins.Carbohydrates(starches and sugars) are compounds of carbon, hydrogen, and oxygen. Living things use carbohydrates as their main energy source. Plants and some animals also use carbohydrates for structural purposes. Simple sugars are called monosaccharides.When two or more monosaccharides join, they are called polysaccharides.Lipids(fats, oils, and waxes) are made mostly of carbon and hydrogen. Lipid molecules are made up of compounds of fatty acids and glycerol.In the body, lipids are used to:•store energy•form parts of membranes•form waterproof coveringsNucleic acids contain hydrogen, oxygen, nitrogen, carbon, and phosphorus. Nucleic acids store and transmit hereditary,or genetic, information.There are two kinds of nucleic acids: DNA and RNA.Proteins are made of nitrogen, carbon, hydrogen, and oxygen. Proteins are polymers of amino acids.Proteins are used to:•control the rate of reactions•regulate cell processes•help form bones and muscles•carry substances into or out of cells•help fight disease2–4 Chemical Reactions and EnzymesEverything that happens in an organism is based on chemical reactions. A chemical reaction is a process that changes one setof chemicals into another set of chemicals. The elements or com-pounds that enter into the reaction are the reactants.The elements or compounds produced by the reaction are known as products. Chemical reactions always involve breaking the bonds in reactants and forming new bonds in products.Some chemical reactions release energy; others absorb energy. Chemical reactions that release energy often occur sponta-neously. Chemical reactions that absorb energy require a source of energy.Every chemical reaction needs energy to get started. The energy that starts a chemical reaction is called activation energy.Some chemical reactions that make life possible are too slow.A catalyst is a substance that speeds up the rate of a chemical reaction. Catalysts work by lowering a reaction’s activation energy.Enzymes are proteins that act as biological catalysts. Enzymes speed up chemical reactions that take place in cells.In an enzyme-catalyzed reaction, the reactants are known as substrates. Substrates bind to a site on the enzyme called an active site. The fit of substrates binding to an active site is so specific that they are often compared to a lock and key. Substrates remain bound to the enzyme until the reaction is done. Once the reaction is over, the products are released.。
化学专业英语第五版
化学专业英语第五版英文回答：Introduction.Chemistry is the study of matter and its properties, as well as the changes that matter undergoes. It is a vast and complex field that encompasses many different branches, including inorganic chemistry, organic chemistry, physical chemistry, analytical chemistry, and biochemistry.Chemistry is essential to our understanding of theworld around us. It plays a role in everything from thefood we eat to the clothes we wear to the medicines we take. Chemistry is also used in a wide variety of industries, including manufacturing, agriculture, and energy production.Importance of Chemistry.Chemistry is important for a number of reasons. First,it helps us to understand the world around us. By studying chemistry, we can learn about the composition of matter, the properties of different elements and compounds, and the changes that matter undergoes. This knowledge can help us to make informed decisions about the products we use and the activities we engage in.Second, chemistry is essential for the development of new technologies. Many of the technologies that we rely on today, such as computers, cell phones, and medical devices, would not be possible without chemistry. Chemistry is also used to develop new materials, such as plastics, ceramics, and composites. These materials are used in a wide variety of applications, from construction to transportation to medicine.Third, chemistry is important for the environment. Chemistry can help us to understand the impact of human activities on the environment and develop ways to reduce our impact. Chemistry is also used to develop new technologies that can help us to clean up pollution and protect the environment.Challenges in Chemistry.Chemistry is a challenging field, but it is also a rewarding one. There are many challenges that chemists face, including:The complexity of matter. Matter is made up of atoms and molecules, which are themselves made up of even smaller particles. Understanding the structure and properties of matter is a complex task.The vastness of chemistry. Chemistry is a vast field that encompasses many different branches. It is impossible for any one person to know everything about chemistry.The rapid pace of change. Chemistry is a rapidly changing field. New discoveries are being made all the time. Chemists must be able to keep up with the latest advancesin order to stay current in their field.Despite the challenges, chemistry is a fascinating andrewarding field. It is a field that is constantly evolving, and there is always something new to learn.中文回答：导言。
高考英语一轮复习语法知识必备：07.名词性从句
【要点巩固】 ①(2024·河南联考) __W__h_a_t_makes the Qatar World Cup unique is the kind of technology China is providing. ②(2024·韶关模拟) But _w__h_a_t_was pleasantly surprising was that the lingering fragrance of the tea and the crunchy texture of the shrimp won the emperor over. ③(2024·潮州模拟) The scientists believe _w__h_a_t_caused whales to get so large was a change in the Earth’s climate only about 3 million years ago.
(2)It+be+形容词+从句 It is necessary that...有必要…… It is clear that... 很清楚…… It is likely that... 很可能…… It is important that... 重要的是…… 类 似 的 可 用 于 该 结 构 的 形 容 词 还 有 :strange 、 natural 、 obvious 、 true 、 good 、 wonderful 、 possible 、 unlikely 、 unusual 、 certain 、 evident 、 worthwhile 、 surprising、interesting、astonishing等。 It is likely that the goods have met with some accident on the way. It is strange that he should have gone away without telling us.
The structure of matter and its properties
The structure of matter and itspropertiesMatter is what makes up everything in the universe, from the smallest particles to the largest stars. It is the physical substance that occupies space and has mass. Matter is made up of atoms, which are the building blocks of elements. Atoms, in turn, are made up of subatomic particles such as protons, neutrons, and electrons.The structure of matter is an important concept in physics and chemistry. Understanding the structure of matter helps us understand its properties and behavior. The structure of matter can be studied at different levels, ranging from subatomic particles to the macroscopic scale.At the subatomic level, matter is composed of particles such as quarks, leptons, and bosons. These particles interact with one another through fundamental forces such as the strong force, weak force, electromagnetic force, and gravitational force. The strong force holds quarks together to form protons and neutrons, while the weak force is responsible for the decay of subatomic particles.Moving up to the atomic scale, matter is composed of atoms, which are made up of a nucleus (containing protons and neutrons) surrounded by electrons. The number of protons in the nucleus determines the element to which the atom belongs. Atoms can also have different isotopes, which have the same number of protons but different numbers of neutrons in the nucleus.The properties of matter depend on its structure. For example, different elements have different chemical and physical properties because of the differences in their atomic structure. The way in which atoms are arranged in a material also has an impact on its properties. For example, diamond and graphite are both made up of carbon atoms, but they have different structures and properties. Diamond is hard and transparent, while graphite is soft and opaque.The properties of matter can be classified as physical or chemical. Physical properties include characteristics such as density, melting point, boiling point, and conductivity. Chemical properties, on the other hand, refer to the behavior of matter in the presence of other substances, such as its ability to react with other chemicals.The behavior of matter can also be described in terms of its states. Matter can exist as a solid, liquid, or gas, depending on the temperature and pressure. These states are characterized by differences in the arrangement and motion of atoms or molecules. For example, in a solid, the atoms or molecules are tightly packed and vibrate in place, while in a gas, they are widely spaced and move freely.The nature of matter is also related to its energy content. Matter can have different forms of energy, including kinetic energy (energy of motion), potential energy (energy of position), and thermal energy (energy related to temperature). These different forms of energy can be exchanged between matter and its surroundings, leading to changes in the matter's properties.In conclusion, the structure of matter and its properties are closely intertwined. Understanding the structure of matter allows us to predict and explain its behavior in different circumstances. Matter's properties depend on its structure, energy content, and the environment in which it is located. This knowledge is fundamental to many areas of science, including physics, chemistry, and materials science.。
流利说 L3 U2 P1 中英文翻译版
L3 U2 P1- 1 States of Matter原文：Matter is made of atoms and molecules.译文：物质是由原子和分子组成的。
原文：Water, for example, is the age to a molecule.译文：例如，水是分子的年龄。
原文：This means that a molecule of water has three atoms.译文：这意味着一个水分子有三个原子。
原文：A water molecule has two hydrogen atoms and one oxygen atom.译文：水分子有两个氢原子和一个氧原子。
原文：Substances like sugar has many atoms in their molecules.译文：像糖这样的物质分子中有许多原子。
原文：A molecule of sugar has many atoms, including carbon, hydrogen and oxygen.译文：糖分子有许多原子，包括碳、氢和氧。
原文：It's the water molecule, Matter is made of molecules such as H, two, O, which is the water molecule.译文：它是水分子，物质是由氢，氢，氧这样的分子组成的，它们是水分子。
原文：Matter can be in one of three states, solid, liquid or gas.译文：物质可以处于三种状态之一，即固态、液态和气态。
原文：Water and ice are the same substance, but they are in different states.译文：水和冰是同一种物质，但它们处于不同的状态。
原文：These states depend on the temperature of the molecules.译文：这些状态取决于分子的温度原文：When we hit a substance, the molecules move faster and try to take up more space.译文：当我们撞击一个物质时，分子运动得更快，并试图占据更多的空间。
2018年专四真题虚拟语气和情态动词-章振邦语法书页数标注
Subjunctive mood(P122, p. 129. P 143 动词过去完成体P181-190, 395)条件句14. “I wondered if I could have a word with you.” The past tense in the sentence refers to a __B___. (p128) 2017A. past event for exact time referenceB. present event for tentativenessC. present event for uncertaintyD. past event for politenessV. in specific contexts, the simple past can also denote the present or the future time. There are two uses. One is known as the attitudinal past (属于“表态性过去时” (attitudinal past), 即表示说话人当前的试探性态度, 而非过去时间, 多用于表示意愿或心理状态的动词) , that is , the past tense is associated with the present time in independent clauses expressing a question, request or suggestion. Its effect is to make the question/request/suggestion less direct, implying a polite, somewhat tentative attitude试探性态度，婉转语气on the part of the speaker.A: Did you want me?B.Yes, I wondered if you could give me some help .Want, wonder, think, hopeThe other is what we call the hypothetical past.The simple past refers not to a fact but to a non-fact, and is typically found in that-clauses following such constructions asIt’s time….I wishI’d ratherSupposeAs if15. “If I were you, I wouldn’t wait to propose to her.” The subjunctive mood in the sentence is used to ____D______.183A. alleviate hostilityB. express unfavorable feelingsC. indicate uncertaintyD. make a suggestionWere-subjunctive has only on form were, which applies to subjects of all persons, is hypothetical or unreal in meaningIf, if only, as if, as though, though,Wish, would rather, suppose, imagine,As it were( so to speak)宛如，好比54.If only the patient ______a different treatment instead of using the antibiotics, he might still be alive now. P 186 2007A.had receivedB.receivedC.should receiveD.were receiving正确答案为A). If only引导的虚拟语气,解释为”要是…该多好啊!”. 与现在的事实相反的则if only后接过去式did,和过去事实相反的则接过去完成时had done. 这里是说要是这个病人接受了不同的治疗方式(其实那个时候并没有接受),与过去事实相反用过去完成时. 句意: 如果那个病人不使用抗生素而是采用其他疗法,他现在可能还活着呢.51.If only I ______ play the guitar as well as you! 2006 P 186 P192A wouldB couldC shouldD might52. 正确答案为B). could表示能够,是一种一般能力. 表示具体能力用be able to . p. 192 If only引导的虚拟语气,表示”要是….该多好啊!”. 句意: 要是我能像你那样把吉他弹得那么好该多好啊!3. If you explained the situation to your solicitor, he ____ able to advise you much better than I can. （2005年51题）2015A. would beB. will have beenC. wasD. were15. If you explained the situation to your lawyer, he _______ able to advise you much better than I can. (2015)(395/381)2005A. will beB. wasC. would beD. were[译文]如果你把情况向你的事务律师说明，他会比我更能给你提出好的建议。
Kinetic Theory of Matter
21
Boiling/Condensation Point (Vaporization)
Change from liquid to gas and gas to liquid.
The Classification and Properties of Matter Depend Upon Microscopic Structure
➢Particle arrangement ➢Particle energy ➢Particle to particle distance
18
Phase Changes
10
States of Matter Solids
Particle Movement Examples
11
States of Matter
Liquids
▪Particles of liquids are tightly packed, but are far enough apart to slide over one another. (intermolecular forces have weakened) ▪Liquids have an indefinite shape and a definite volume. ▪So, liquids take the shape of whatever container they are in but they cannot be squeezed into a smaller volume
Same temp.; if boiling, particles are gaining energy; if condensing, particles are losing energy.
名词性从句翻译
主语从句1、这个教材是否可用于我们的学校还未讨论过。
(whether)2、使我最感到吃惊的是他态度的突然转变。
(what)3、2010年世博会将在上海举行已成定局。
(that)所有国家都同意，绝不攻击带有红十字标记的任何物体。
(whatever)这次计划将如何执行仍需讨论。
(how)一本书是否畅销取决于诸多因素。
(Whether)(上海市高考题)以it为形式主语的主从复合句他看来不愿意对这件事作进一步的评论。
(seem)你喝了那么多咖啡难怪你睡不着。
(no wonder)据估计，飞到火星上来回一趟需要一年半多的时间。
(estimate)他碰巧以前做过类似的练习。
(happen)他真的打算一路乘火车去莫斯科。
(true)一切物质都是原子构成的，这是众所周知的事实。
(fact)这种材料能否用在我们工厂还是一个问题。
(question)业已证明他们的建议在一定程度上是合理的。
(prove)原来他根本没出过国，也根本不是华侨。
(turn out)下一班火车什么时候去西藏通知了没有(announce)新产品销路好不好取决于它的质量。
（whether）据报道这种野生植物含有丰富的维生素。
（It）(上海市高考题)宾语从句汤姆希望成为任何一个能与他分享兴趣的人的朋友。
(whoever)他们祖父当时也算是第一批就在这如今著名旅游胜地的地方安家的。
(what)除非下雨，这位老人每天都散步。
(except)我们问门卫办公室下午五点是否还开着。
(whether)我爸爸说我可以选任何一件看上去适合我的衣服。
(whichever)我们应该仔细地取出任何可能对年轻人有害的东西。
(whatever)你能否告诉我为什么离开教室时不关灯(why)他除了喜欢偶尔下下棋外没多少别的爱好。
(except)以IT为形式并与的主从复合句不要想当然地认为所有问题通过一次讨论就能解决。
我们认为每个市民都讲礼貌是很重要的。
我们已把问题说清楚，吸烟对女性有更大的危害。
BCSciencefinalReviewBC省十年级科学省考复习
The atoms share electrons.
Sodium Chloride Ionic Bond – Steals Electrons!
Sodium Chloride Lewis
_______________________________ (c) How many electrons are in an iron(III) ion? _________2_6_____________________
23
Bohr Diagrams
Each orbit can hold up to a certain number of electrons.
C. nuclei D. protons
A) What is everything made of?
• Everything on earth is made of matter物质. Matter is anything that has a mass and takes up space. Matter is made of atoms物质是由原子组成的. Atoms are basic基本的 building blocks of chemistry.
Polyatomic Ionic Compounds 多原子离子化合物
Sodium Bromide 23. Write the names of the following ionic compounds.
(a) NaBr ________________________________________________
matter英文作文例文
matter英文作文例文英文：Matter is something that is present in the universe and has mass and volume. It can exist in different forms suchas solid, liquid, or gas. Matter is made up of tinyparticles called atoms, which are the building blocks of everything around us.Matter is important because it makes up everything we see and touch. Without matter, there would be no physical world. It is also important in science because it helps us understand how the universe works. For example, studyingthe properties of matter can help us understand howdifferent materials behave under different conditions.In everyday life, matter is all around us. When we cook food, we are using matter in the form of ingredients. When we drive a car, we are using matter in the form of gasoline. Even the air we breathe is made up of matter in the form ofgases.Overall, matter is essential to our existence and understanding of the world around us.中文：物质是存在于宇宙中具有质量和体积的东西。
物质英文作文怎么写
物质英文作文怎么写英文回答：Matter is the substance of all things in the universe. It is made up of atoms, which are the smallest units of matter that still retain the chemical properties of an element. Atoms are composed of even smaller particlescalled protons, neutrons, and electrons.Matter exists in three main states: solids, liquids, and gases. Solids have a fixed shape and volume. Liquids have a fixed volume but can take the shape of their container. Gases have no fixed shape or volume and can expand to fill their container.The properties of matter are determined by the arrangement of its atoms and molecules. For example, solids have a rigid structure because their atoms are tightly packed together. Liquids have a less rigid structure because their atoms are more loosely packed. Gases have theleast rigid structure because their atoms are widely spaced apart.Matter can be changed from one state to another by adding or removing energy. When energy is added to a solid, it will melt and become a liquid. When energy is added to a liquid, it will vaporize and become a gas. When energy is removed from a gas, it will condense and become a liquid. When energy is removed from a liquid, it will freeze and become a solid.Here are some examples of matter:Air is a gas. Air is composed of nitrogen, oxygen, and other gases.Water is a liquid. Water is composed of hydrogen and oxygen atoms.Ice is a solid. Ice is composed of water moleculesthat are frozen into a rigid structure.A rock is a solid. A rock is composed of various minerals, which are composed of different elements.中文回答：物质是宇宙中所有事物的根基。
高三英语同位语从句功能单选题40题
高三英语同位语从句功能单选题40题1.The news that he won the first prize excited everyone.A.whichB.thatC.whatD.when答案：B。
本题考查同位语从句。
“that he won the first prize”是对“news”的解释说明，且在从句中不充当任何成分，故用that 引导。
选项 A which 在定语从句中充当主语或宾语；选项C what 在名词性从句中充当主语、宾语等成分；选项D when 在定语从句或名词性从句中作时间状语。
2.The fact that he is honest is known to all.A.whichB.thatC.whatD.where答案：B。
“that he is honest”是对“fact”的解释说明，在从句中不充当任何成分，用that 引导。
选项A which 在定语从句中充当成分；选项 C what 在名词性从句中充当成分；选项 D where 在定语从句或名词性从句中作地点状语。
3.The idea that we should help each other is popular.A.whichB.thatC.whatD.how答案：B。
“that we should help each other”是对“idea”的解释说明，在从句中不充当成分，用that 引导。
选项 A which 在定语从句中充当成分；选项C what 在名词性从句中充当成分；选项D how 在名词性从句中作方式状语。
4.The thought that he might be late worried him.A.whichB.thatC.whatD.when答案：B。
“that he might be late”是对“thought”的解释说明，在从句中不充当成分，用that 引导。
选项A which 在定语从句中充当成分；选项C what 在名词性从句中充当成分；选项D when 在定语从句或名词性从句中作时间状语。
物质与材料英语作文模板
物质与材料英语作文模板英文回答：Matter and Materials。
Matter is anything that has mass and takes up space. It is made up of atoms, which are the smallest units of matter that still retain the properties of the element. Atoms can be combined to form molecules, which are the building blocks of all matter.Materials are substances that are used to make objects. They can be classified into three main types:Natural materials: These are materials that are found in nature, such as wood, stone, and metal.Synthetic materials: These are materials that are made by humans, such as plastic, concrete, and glass.Composite materials: These are materials that are made from a combination of natural and synthetic materials, such as fiberglass and carbon fiber.Materials have different properties that make them suitable for different applications. Some of the most important properties of materials include:Strength: The ability of a material to withstand stress without breaking.Hardness: The ability of a material to resist being scratched or deformed.Toughness: The ability of a material to absorb energy without breaking.Flexibility: The ability of a material to bend without breaking.Corrosion resistance: The ability of a material to resist being damaged by chemicals or moisture.The choice of materials for a particular application depends on the specific requirements of the application.For example, a material that is strong and durable is needed for a bridge, while a material that is lightweight and flexible is needed for a parachute.中文回答：物质与材料。
高翻6.3作业
1．The people who had been evacuated have returned and rebuilt their town.被疏散的人们已经返回并重建了他们的家园。
2. Atoms are the units out of which molecules are built.原子是组成分子的基本单位。
3. Those who want to go please sign their names here.想去的人请在这儿签一下名。
4. We will start at the point where we left off.我们应该在从我们停止的地方再开始。
5. It is a question that needs careful consideration.这是个需要仔细考虑的问题。
6. I know of a place where we can swim.我知道有个我们可以去游泳的地方。
7. The days are gone when my heart was young and gay.那些对我来说年轻快乐的日子已经不在了。
翻译句子,注意运用后置译法1．All matter is made of atoms, which are invisible to the naked eye.所有的东西都是原子组成的，而原子肉眼不可见。
2．He is fond of music, which I am glad to hear.他喜欢音乐，我听到这个后非常开心。
3．An aircraft engine consists of thousands of parts, each of which has its importance.一个飞机包括数以万计的部件，其中每一个部件都非常有用。
4．Energy can neither be created nor destroyed, which is the universally accepted law.能量既不能被创造，也不会凭空消失，它遵循宇宙守恒原理。
The Atom and the Periodic Table原子与元素周期表
Ex: Gold = Au
The symbol is either:
1. One capital letter
-ex: Carbon = C
2. Two letters…one capitol, one lower case
Electrons have a negative charge (-) and have almost no mass at all.
Atomic Structure
Subatomic = smaller than an
atom
Atoms are made up of three subatomic particles:
Live where?
Have mass?
What charge?
Protons In nucleus 1 a.m.u
+
Neutrons In nucleus 1 a.m.u
none
Electrons Outside
No,
-
nucleus negligible
Atomic Structure Video
Except Al (this is a metal!!!)
Properties of both metals and nonmetals
Less conductive than metals, but poorer insulators than nonmetals
Electrons held more tightly than metals, but can be freed with heat
全英化学资料 atoms1
The Spacious Atom
Microcosms of our solar system, atoms are dominantly empty space:
electron orbits
If an oxygen atom had a total radius of 100 km, the nucleus would be a ~1 m diameter sphere in the middle.
Each atom can be described by its atomic weight (or mass), which is the sum of the protons and neutrons.
lithium: atomic number = 3 3 protons 4 neutrons atomic weight = 3 + 4 = 7
BUT... although each element has a
defined number of protons, the number of neutrons is not fixed. Atoms with the same atomic number but variable numbers of neutrons are called isotopes.
C = carbon P = phosphorus K = potassium Ti = titanium Mn = manganese
Atomic Weight: It’s all in the Nucleus
Since electrons weigh virtually nothing, the mass of an atom is concentrated in its nucleus.
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Discovery of Atomic Structure
• 1800s- scientists thought atom was a tiny solid ball.
• Finding Atomic Mass on Periodic Table • Located below element symbol on periodic
table.
(Section 2):Electrons in Atoms
Energy of Electrons • Why electrons don’t crash into the nucleus:
atom is neutral in charge.)
– Ex: atomic number of carbon, C = 6 – Question: how many protons? How many
electrons? How many neutrons?
Slide 2.2
Isotopes
• The number of neutrons can vary from atom to atom in an element.
Bohr’s Model of Atom
• Neils Bohr studied w/Rutherford
• His model is also called the planetary model
• He discovered that e-s could only exist at certain distances from the nucleus.
• Atoms of the same element w/different #s of neutrons are called ISOTOPES.
• In order to know how many neutrons in an atom you must be told.
• The mass number tells you how much mass the
• He send electricity through the tube and saw
– A bright ray travelling from the negative end (cathode) to the positive end (anode). “cathode rays”
– picture of cathode ray tube – Cathode ray bends toward a positive end of a
magnet. – “ “ bends away from a negative end of a magnet.
Cathode Ray Experiment
• Conclusion: 1. The cathode ray was actually ____ charged
particles. 2. The atom could not be ________ as scientists
Composition of Atoms
• Protons: positive charge, in nucleus, are heavy, “p+”
• Neutrons: no charge, in nucleus, are heavy, “n0”
• Electrons: negative charge, outside nucleus “electron cloud”, very light (1/1840 of a proton or neutron), “e-”
• They coined the word “atom” meaning cannot be broken.
“Modern” Atomic Theory
• Lavoisier (1743-94) law of conservation of matter
– Matter is neither created nor destroyed – Matter never “goes away,” even when an object is
but different from atoms of other elements.
Hypotheses, Theories, Laws (review)
• Hypothesis: testable prediction to explain an observation
• Theory: well tested explanation that explains many observations. May change over time
energy, will you stay close to the nucleus or will you move further from it?
Answer: you may still stay in “orbit” but you will be able to move further away from the nucleus.
Charges in an Atom
• The + charge on a proton is equal to the charge on an electron.
• Atoms are neutral (have no overall charge) • Therefore, the # of protons = # electrons in an
had thought, but must contain charged particles.
Discovery of Protons & Neutrons
• Later scientists realized there was a second ray in the vacuum tube.
(Kind of like planets in orbit around the sun.)
Energy of Electrons (cont.)
(Don’t write this!)
DISCUSS WITH YOUR NEIGHBOR: • You are an electron. If you have a lot of
• THEN…JJ Thomson (1897) discovers the electron (e-)
JJ Thomson Cathode Raye (no air inside) w/ electrode on each end, attached to a terminal.
Chapter 2: Matter is Made up of Atoms
Early Ideas About Matter
• Greek philosophers (2500 y.a.) proposed matter was made of 4 elements: earth, air, fire, water.
they have enough energy to keep them away. • Why e-s (usually) don’t fly off of atoms: they
have enough attraction to the nucleus to keep them in “orbit.”
• In 1910 Thomson discovered that neon atoms have different masses.
• Conclusion: there must be another particle that has no charge, called a neutron.
Discovery of Nucleus
atom.
Atomic number
– determines the identity of the atom. – It tells us the number of protons in the atom. – It also tells us the number of electrons (b/c an
atom has. – Since p+ and n0 are the heavy parts, – mass # = # of p+’s + n0’s.
QUESTION: If the mass number of a carbon atom is 14,
• How many protons? • How many electrons? • How many neutrons?
– it has 6 p+ and 6 n0, – 1 a.m.u = 1/12 the mass of a carbon-12 atom.
Atomic Mass
• (definition) Weighted average of all the isotopes of an element. See p 68 of text. calculating atomic mass
– It bent toward the – end of a magnet. – It bent away from the + end of a magnet. – Therefore, this ray was made of _____ charged
particles.
Discovery of Protons & Neutrons, cont.
burnt, eaten, etc. – Atoms are just rearranged into new matter.