文档库 最新最全的文档下载
当前位置:文档库 › 作文+翻译

作文+翻译

作文+翻译
作文+翻译

All of us are living in a world full of various temptations.And some temptations are too tempting for them to resist. Just for this reason, many people can not get out from the temptation and they make wrong decisions which do bad to their work and life. For example, some students ruin their study because they are addicted to the computer games.As time goes by, they lose themselves when they are confronted with temptation.

As the saying goes by, where there's a will, there's a way.It is so significant for us that we should say no to temptation.On the contrary, we ought to form a good habit..First of all , we must make a strong determination to resist temptation.To achieve this, stay away from temptation from various aspects, such as smoking and playing computer games.Further more, make a comprehensive plan and practical goal.Only when we have a definite plan, can we pay

more attention to our study.In this way,we will get double the result by doing half the work. Last but not least , maintaining an optimistic attitude is also essential.

In a word , cultivating good habits rely on a strong will.we should try our best to resist temptation.Only in this way, can we better our life and work.

All of us are living in a world full of various temptations.And some temptations are too tempting for them to resist. Just for this reason, many people can not get out from the temptation and they make wrong decisions which do bad to their work and life. For example, some students ruin their study because they are addicted to the computer games.As time goes by, they lose themselves when they are confronted with temptation.

As the saying goes by, where there's a will, there's a way.It is so significant for us that we should say no to temptation.On the contrary, we ought to form a good habit.First of all, we must make a strong determination to resist temptation.To achieve this, stay away from temptation from various aspects, such as smoking and playing computer games.Further more, make a comprehensive plan and practical goal.When we have a definite plan, we can pay more attention to studying.In this way, we can get double results by doing half the work. What is more, maintaining an optimistic attitude is also essential.

In a word, a strong will to develop good habits is essential.we should take some effective steps and try our best to resist temptation.In this way, we can better our life and work.

Thirdly, the breadth of issues to be covered by this visit is widely

In their talks, the Premier and the Prime Minister will have an in-depth exchange on a broad range of international and regional issues. Their discussions will help to consolidate the two countries’ consensus an d build on existing cooperation on issues such as world peace and security, common development and global challenges.

The prime ministers of the two countries present at the round-table with heads of international economic and financial institutions .It will send strong signals on reforming international economic and financial governance; and reinforcing global economic and financial cooperation. It will boost confidence in the outlook of the global economy.During the visit, there will also be a symposium on the subject of free trade zones, which is expected to play a leading role in contributing to the prospect of a future China-EU FTA; and strengthen cooperation on China’s free-trade-zone initiative.

Through the speech Premier Li will deliver to over 300 members and audience of two top British think-tanks, he will elaborate on China’s development and the better place our world is and will be as a result. I believe his insights, shared here in the UK, will greatly improve the understanding of China in Britain, in Europe and beyond.

实用英文写作与翻译作业与参考答案21

实用英文写作与翻译2-1作业及参考答案 第一次作业: Americans Eat Out More often and Less Healthfully Although food cooked at home is far more healthful than meals eaten at restaurants, Americans are dining out more than ever, the U.S. Agriculture Department said Tuesday. Restaurant food accounted for([在数量,比例方面] 占) 39 percent of U.S. meals bought in 1996, up from 26 percent in 1970, the department said in a report, ``Away-From-Home Foods Increasingly Important to Quality of American Diet.'' ``While(尽管)the nutritional quality(营养质量)of foods consumed by Americans has improved overall, foods prepared at home are generally much more healthful than away-from-home foods,'' the department said. ``Despite nutritional gains at home, Americans will find it difficult to improve their diets because they purchase so many meals outside the home,'' the study said. While (尽管)the nutritional content of food prepared both at home and in restaurants has improved in recent years, food eaten out contains more of the nutrients Americans typically(一般地;通常)eat too much of, including fat and saturated fat(饱和脂肪), and less of what is lacking from most diets, such as calcium, fiber and iron. The department recommended nutrition education programs should place more emphasis on teaching U.S. consumers about how to order healthful meals when dining out. Improved diets have been found to prevent risk of heart disease, stroke(中风), cancer, diabetes(糖尿病), osteoporosis-related hip fractures(与骨质疏松症有关的髋关节骨折) and neural tube birth defects(神经管先天缺损). Osteoporosis-related hip fractures cost up to $10.6 billion each year in the United States in medical care expenses, missed work and premature deaths(早亡), the department said. 参考译文:美国人外出用餐频繁而饮食健康水准美况愈下 据美国农业部星期二称尽管在家煮烧的食物远比餐馆里所用之餐有益于健康,美国人外出用餐更频繁。餐馆里的食物占1996年美国人购餐的39%,比1970年增长了26%。该部门在报告中称:“外出所用之餐对于美国人饮食质量日益重要”。该部门还称:“虽然美国人消费的食物的营养质量总体改善了。但是,一般来说,家里所备的食物远比外出用餐的食物有益于健康。”研究表明:“尽管在家里用餐能获取养份,美国人发觉他们难以改善自己的饮食,因为他们多次在外购餐。”近年来在家里和餐馆里所备的食物的营养结构都得到了改善,然而,外出用餐的食物包含了较多典型的美国人汲取过多的养份,包括脂肪和饱和脂肪,也包含了较少多数饮食中所缺少的,如钙,纤维和铁。该农业部提议营养教育计划应更着重于教导美国消费者外出用餐时如何预定有益于健康的一餐。人们发现改善后的饮食结构能预防心脏病,中风,癌症,糖尿病,与骨盆炎相关的髋部骨折以及试管婴儿的神经缺陷所带来的危险。该部门称,在美国与骨盆炎相关的髋部骨折每年在医疗照料费用,医疗失误和早产死亡之上的耗费高达106亿美元。 第二次作业 1、Kill one’s appetite ?Kill time ?Kill the peace ?Kill the mood ?Kill the proposal ?Kill the engine ?Kill the child with kindness 2、If the doctor had been available, the child would not have died. 3、This ticket is available in all parks. 4、I’ll have Mr. Perkin call you back as soon as he is available.

翻译&作文

Unit 1 段落翻译题(出题者:梁凌) 六年前,作者经历一场惊险的旅程。这次经历让他印象深刻,因为他在这场紧急的事故中找到了真正的英雄。一个周五的早上,航班前往亚特兰大(Atlanta)。飞机起飞不久,飞行员向乘客通报紧急情况:一个引擎失控了,液压系统(hydraulic system)已经失灵了。更糟糕的是,他们都将会坠机。忽然间,机舱里一片恐慌。许多乘客脸色苍白,四周都在哭喊。在混乱中,一把温柔冷静的妇女声音传来,她正在安慰自己的女儿。母亲似乎没有被四周的悲伤和恐惧影响。即使面对死亡,她依然坚定地告诉女儿她有多么爱她,她把女儿包裹在怀里,尽可能地保护她。幸运的是,飞机安全着陆。母亲对女儿的那份爱向人们展现了什么是真正的勇气。 The author went through a breathtaking travel six years ago and the experience impressed him deeply because he found a real hero in that emergency. On one Friday morning, a flight headed for Atlanta. Soon after the plane took off, the pilot announced the urgent crisis that one engine was broken and the hydraulic system had failed. Worse still, they might be about to crash. Suddenly, panic spread all over the crowd. Many passengers look grim and pale. All around, people cried and screamed. In the chaos, there was a soft and calm voice from a woman who was trying to comfort her daughter. The mother seemed undisturbed by the sounds of grief and fear around her. Even when facing death, the mother still told her daughter firmly about how much she loved her, and put her body over her daughter, trying to protect her as much as she could. Fortunately, the plane landed safely. The mother’s love for her daughter showed people what real courage was. 作文(出题者:梁凌) ? 1. Who is your favorite hero/heroine? And why do you like him/her? ? 2. Should everyone have a hero model? ? 3. What is your own opinion? Unit 2 段落翻译题(出题者:梁凌) 我告诉他,我绊倒在地时,听到了撕裂声。然而他,我的丈夫,不但不理会我说的,而且声称,一定是我鞋带的问题。所以,即便我的我的脚肿的像个气球,但我们并不知道我的脚崴了,因为他没有将我送去看医生。在去机场的12个小时飞行中,他把我一个人扔在借来的轮椅上,完全没有注意到我要去洗手间的手势。 my husband, not only dismissed what I said but also contended that it must have been the strap on my shoes snapping. Therefore, we didn’t know my foot was broken because he didn’t send me to a doctor even though my foot was swollen like a balloon. During the 12-hour flight to the airport, he left me alone in the borrowed wheelchair and pretended that he didn’t notice my gestures indicating the need of going to the bathroom. 作文(出题者:梁凌) 1. 当代人的沟通渠道各种各样,主要分为语言类沟通方式和非语言类沟通方式,譬如…… 2. 人们产生误会的主要原因包括…… 3. 我认为最好的沟通方式是……,因为……

初一英语作文带翻译

初一英语作文带翻译 各位读友大家好,此文档由网络收集而来,欢迎您下载,谢谢篇一:My favorite season If you ask to me favorite season? I to say: my favorite season is fall. Because fall is cool and windy but isn’t too hot and too cold. I like reader relaxed and happy feeling. The climate is cool and pleasant in autumn, not so hot in summer nor so cold in winter. Autumn is the harvest season, golden rice in the paddy fields are ripe. Under the rays of the Sun in a piece of gold, Maple fell on a piece of Red Maple leaves, dancing in the air like a beautiful butterfly. moreover fall will come, farmers can harvest theirs “fruits of lador” The most exciting still can eat many tasty fruits. Such as: oranges,mangos, bananas, apples, pears……

高考英语满分作文【五篇】(附翻译)

高考英语满分作文【五篇】(附翻译) 导读:本文高考英语满分作文【五篇】(附翻译),仅供参考,如果觉得很不错,欢迎点评和分享。 导语:以下是小编精心为大家准备的高考复习二轮英语专题《高考英语满分作文》,有了它,妈妈再也不用担心我的学习。 高考英语满分作文一(附翻译)假设你叫王明,昨天收到了笔友David的e-mail,得知他不久要到北京来学习中文。他想了解如何学好中文。请你用英文给他回复一封e-mail,介绍学习中文的体会和方法,提出你的建议,以及表达你帮助他学好中文的愿望。 【例文】 Dear David, I'm glad you'll come to Beijing to learn Chinese. Chinese is very useful, and many foreigners are learning it now. It's difficult for you because it's quite different from English. You have to remember as many Chinese words as possible. It's also important to do some reading and writing. You can watch TV and listen to the radio to practise your listening. Do your best to talk with people in Chinese. You can learn Chinese not only from books but also from people around you. If you have any questions, please ask me. I'm sure you'll learn Chinese well. Hope to see you soon in Beijing.

英语翻译题20套(带答案)

英语翻译题20套(带答案) 一、高中英语翻译 1.高中英语翻译题:Translation: Translate the following sentences into English, using the words given in the brackets. 1.究竟是什么激发小王学习电子工程的积极性?(motivate) 2.网上支付方便了客户,但是牺牲了他们的隐私。(at the cost of) 3.让我的父母非常满意的是,从这个公寓的餐厅可以俯视街对面的世纪公园,从起居室也可以。(so) 4.博物馆疏于管理,展品积灰,门厅冷落,急需改善。(whose) 【答案】 1.What on earth has motivated Xiao Wang’s enthusiasm/ initiative to major in electronic engineering? 2.Online payment brings convenience to consumers at the cost of their privacy. 3.To my parents’ satisfaction, the din ing room of this apartment overlooks the Century Park opposite the street and so it is with the sitting room. 或者What makes my parents really satisfy is that they can see the Century Park from the dining room of this apartment, so can they from the living room. 4.This museum is not well managed, whose exhibits are covered with dust, and there are few visitors, so everything is badly in need of improvement. 或The museum whose management is reckless, whose exhibits are piled with dust and whose lobby is deserted, requires immediate improvement. 【解析】 1.motivate sb to do sth 激发某人做某事,on earth究竟,major in 以…为专业,enthusiasm/ initiative热情/积极性,故翻译为What on earth has motivated Xiao Wang’s enthusiasm/ initiative to major in electronic engineering? 2.online payment网上支付,brings convenience to给…带来方便,at the cost of以…为代价,privacy隐私,故翻译为Online payment brings convenience to consumers at the cost of their privacy. 3.To my parents’ satisfaction令我父母满意的是,后者也那样so it is with。也可以用主语从句What makes my parents really satisfy 表语从句thatthey can see the Century Park from the dining room of this apartment。overlooks俯视,opposite the street街对面,living room 起居室。故翻译为To my parents’ satisfaction, the dining room of this apartment overlooks the Century Park opposite the street and so it is with the sitting room.或者What makes my parents really satisfy is that they can see the Century Park from the dining room of this apartment, so can they from the living room. 4.not well managed/ management is reckless疏于管理,be covered with dust/ be piled with dust被灰尘覆盖,few visitors游客稀少,be badly in need of improvement/ requires immediate improvement亟需改善。故翻译为his museum is not well managed, whose exhibits

翻译文章

Appendix Research Car from the Academe From October, 1979 to September, 1981, about 35 student engineers and instructors at four technical universities in West Germany worked full time to create a research car. They were sponsored in part by a grant from the BMFT. The project was coordinated by Professor Bert Breuer in Darmstadt. The result is a roomy family car with sedan/wagon profile, diesel power, and front-wheel drive. The project came into being under the same BMFT program in which Audi, Mercedes-Benz, and V olkswagen participated. But in September, 1981 it was announced that only the Uni-Car (University-Car) qualified for continued BMFT funds. Support for the other projects was terminated. This left the car companies to pursue their research an development work independently. Whether the Uni-Car is better than what the motor industry can com up with or not, it is worth a closer look. A lot of thought has gone into it, and some of the solutions are daring yet realistic. The universities placed greater emphasis on passive safety than the car companies. Throughout the car, its designers have aimed for new solutions in simplified maintenance, easier repairs, and longer life. Suitability for mass production also has been a fundamental requirement. Foremost among the design objectives was a 25-mpg average fuel

四级英语作文和翻译

1.Suppose a freshman asks you about the campus life,describe it to him and give your suggestions. On Campus Life Campus is a large stage to show yourselves because there are various kinds of activities awaiting you. Thrilling parties such as freshman initiation party offer you valuable chances to show your talents, enjoy yourselves and make new friends. Volunteering service, a worthy choice to serve people, gives you achievement and happiness. With many English lovers and foreigners,English corner is a good place for you to practice your oral English. Being immersed in these exciting activities you might be a little puzzled. Actually you need not participate in all of them.Self-management and self-control is necessary in college.It is wise to make a plan that fits your personality,interest and future development and follow it strictly.Do not be bothered by trivial things or distracted by online games which are nothing but a waste of time. If you can follow the suggestions above,you are bound to get the most out of your campus life. 翻译:改革开放政策使中国经济迅猛增长,令中国社会发生了巨大变化,同时,越来越多的农民工离开农村到城市工作,在城市中担任建筑工人、工厂工人、餐厅服务员和司机。他们跟城市工作者一起,把中国变成了世界工厂,为中国经济的增长做出了巨大贡献。然而,这一庞大群体却面临着诸多问题,如缺乏工伤赔偿和子女上学难等。 The reform and opening up policy brings rapid economic growth and great social changes to china. In the meanwhile, an increasing number of rural migrant workers have left their land in the countryside to work in cities as construction and factory workers, restaurant staff and drivers . Together with urban labors, they turn China into the factory of the world and contribute a lot to China’s fast-growing economy. However, the huge group is facing various problems such as a lack of industrial injury compensation and schooling for their children.

英语翻译及写作评分标准

MBA翻译评分等级(一般介于5--13之间) 1)EXCELLENT TRANSLATION,分数在14-15分 要求:The translation faithfully reflects all the original passage with only 1 or 2 minor errors in vocabulary, syntax, punctuation or spelling. The translation is elegant appropriate choice of words, a variety in sentence patterns。 2)GOOD TRANSLATION WITH FEW INACCURACIES,分数在11-13分要求:The translation reflects almost all the original passage with relatively few significant errors of vocabulary, syntax, spelling or punctuation. The translation is readable generally clear, smooth and cohesive。 3)PASSABLE TRANSLATION WITH SOME INACCURACIES,分数在8-10分要求:The translation adequately reflects most of the original passage with occasional errors of vocabulary, syntax, spelling or punctuation. The translation is, for the most part, readable. 4)INADEQUATE TRANSLATION WITH FREQUENT INACCURACIES,分数在5-7分要求:The translation only reflects about half of the original passage with frequent errors of vocabulary, syntax, spelling or punctuation. The translation is, in some parts, unreadable. 5)POOR TRANSLATION,分数在1-4分 要求:The translation reflects less than half of the original passage. Almost all sentences contain errors of vocabulary, syntax, spelling or punctuation. The translation is, for the most part, unreadable. 其他标准: 1.如果句子译文扭曲原文意思,该句得分最多不得超过0.5 分。 2.如果某考生给出两种或两种以上的译法,若均正确,给分;若其中一种译法错误,不给分。 3.汉语错别字,不个别扣分,按整篇累计扣分。在不影响意思的前提下,满三个错别字扣 0.5 分。 另:可参考2011年阅卷标准 最高13分,极个别翻译得非常好的才可以给14分,不能给15分 所有内容都翻译的,不管翻译得如何,最低可以得6分 翻译完整,得分在6~13分之间,具体评分标准如下: (a)12~13分:全文翻译流畅,意思基本没有偏差,1-3个词汇点翻译得不准确 (b)10~11分:全文翻译基本流畅,意思没有重大偏差,4-6个词汇点翻译得不准确, 1-2个句子意思有较大偏差 (c)8~9分:全文翻译基本流畅,基本能体现原文意思,有3-5个句子意思有较大偏差,5个以 上词汇点翻译得不准确 (d)6~7分:全文翻译完整,能抓住一些重点词汇,个别句子能体现原文意思 在以上评分标准的基础,如果没有翻译完整,少翻译一句根据句子长度再减1~2分。翻译部分内容的,最低可得3分

英语作文和翻译答案

Unit 1 课后作文范文 Sample 1: My Father It’s said that mother’s love is the greatest love in the world, but if you can notice some small things, you’ll find that father’s love is also the greatest. My father, as a man, usually hide the deep love for behind the c ool face. Don’t have much to say, while sitting with me, but what he has done for me clearly show that he loves even more than himself. I still remember the night, when the wind blowed crazily, he stood in the rain, at the bus stop, waiting for me, quietly. Though he had stood in rain for hours, the only sentence from his mouth was “OK, Let’s go home!” I’ll never forget the love by my dear mother, I’ll also concrete the figure in the

高中英语作文范文与翻译

一、议论类 Bikes or Cars Americans like to go out by car. Although more and more Chinese own cars,most Chinese still like to ride bicycles. This is determined by a lot of factors. As we all know, the bike advances slowly by manpower, but it can be placed wherever it is convenient. However, as for the car, although it can run fast by engine, it must be parked at parking places. Most Americans live in the suburb which is far from urban areas and their working places. So they need cars to go shopping and go to work. And they also like traveling far. Thus a car brings them great convenience. On the contrary, most Chinese live near their working areas and markets. They don't need a car to go to work or go shopping. I would like to ride a bike, because it costs little and it is easy to use and won't cause pollution. 自行车还是汽车 美国人喜欢乘汽车外出。尽管越来越多的中国人拥有了汽车,但大部分中国人仍喜欢骑自行车, 这是由很多因素决定的。 众所周知,自行车靠人力,行进慢,但可以在方便的地方停放。然而对于汽车来说,虽然它依靠发动机行进很快,但它必须停在停车场。 多数美国人生活在郊区,远离市区及工作地点,所以他们需要汽车来购物、上班,并且他们也喜 欢驾车远行。因此汽车给他们提供很大方便。相反,多数中国人居住在工作地点和市场附近,他 们不需要开车去上班或购物。 我喜欢骑自行车外出,因为它花费少而且容易使用。最重要的是自行车不会引起污染。 Smoking And Health Today smoking is a widespread habit all over the world. Not only the old, the youth, but also middle school students have been engaged in smoking. Many of them think that smoking is a smart symbol. However, smoking is harmful to one's ,health. It contributes a lot of lung cancer, from which many people have died in the past years. It can also cause many other diseases. In a word, if you smoke, you do have a much greater chance of losing your health. Furthermore, scientific research shows that smoking is not only harmful to smokers themselves, but also a threat to public health, especially to women and children. Therefore, many countries have made laws forbidding smokers to smoke in public places such as cinemas, stations, hospitals, and so on. Give up smoking! If you don't smoke, don't start. Give up smoking for the sake of your health, for the sake of your family, and for the sake of the whole world. 吸烟与健康 现在,吸烟是一个世界范围的习惯,不仅老年人、青年人吸烟,就连中学生也加入到这个行列中来,他们中的许多人认为吸烟是一种潇洒的象征。 然而,吸烟对人的健康是有害的,它会引起肺癌,在刚刚过去的几年中;许多人因此而丧命,还可能引发其他的疾病。总之,如果你吸烟的话,你就很可能失去拥有健康的机会,更进一步说,科学研究显示,吸烟不仅危害吸烟者本人,而且对公共健康来说,也是一个凶兆,尤其是对妇女和孩子。因此,许多国家都制定了不准在公共场合吸烟的法规,例如:电影院,车站,医院等地。 戒烟吧,如果你还未染上,请不要开始;戒烟吧,为了你的健康,为了你的家庭的健康,为了整个世

初二优秀英语作文带翻译

初二优秀英语作文带翻译 初二优秀英语精选作文带翻译篇一 This summer, I mo*e to a new city with my parents, and Itransfer to a new school. Iused to li*e in the countryside, so my new life is so different from before. The school is a little far from my home, so I go to school by bus. After school, I ha*e many acti*ities in school. Classmates are friendly to me. I learn English now. It's so interesting that I like it *ery much. Besides, life in city is different. There are many interesting places to go. At weekends, my parents take me outside. We go to the park, the zoo or go shopping. But we are not so familiar with our neighbors. I think we should build good relationship with them. 这个夏天,我和爸爸妈妈搬到了一个新的城市生活,我也转到了新的学校上学。以前,我住在乡下,所以我现在的生活和以前有很大不同。学校离我的家稍远,所以我要坐公交车去上学。课后,我在学校有很多活动。同学们对我也很友好。现在我开始学英语了,这门课程很有趣,我很喜欢。另外,在城市里的生活也很不一样,有很多好

unit 1(SS)课文译文、翻译作文参考及单词用法(1)

Unit 1 Translation of the Text A 商品进出口 对大多数国家来说,进出口是国际收入和支出的主要来源。进出口的对象主要指的是货物和服务。有形产品,由于其出入境的可见性常被看作是有形进出口。这些概念广泛应用于商品进出口的实际操作中。 出口 间接出口 许多间接出口贸易中都会涉及中间人。有好几种中间人: 收费代理商 收费代理商扮演着联系你的产品或服务与特定的外国购买商的“掮客”的角色。一般来说,代理人或掮客并不会履行订单,而是把它们交给你,让你来决定。 出口代理公司(EMC) 出口代理公司是“不在场”的出口部门,向潜在的海外买家推荐你的产品以及其他公司的产品。 出口贸易公司(ETC) 出口贸易公司的作用,许多都和出口代理公司一样。然而,作为买卖双方的中间人,他以需求为动力,以交易的达成为导向。这样的定位对于制造商来说就能减少与出口相关的风险。 出口贸易商/出口代理商 出口贸易商或出口代理商会买进产品然后重新包装来出口,他们承担全部的风险,把产品卖给自己的顾客。 直接出口 虽然间接出口有许多的优点,但是直接出口也有自己的优势。虽然初期投入比较多,相关风险也比较大,但是其利润也相应更高一些。 销售代表 海外销售代表相当于制造商在国外的代理人。他们利用公司的产品目录和样品向潜在顾客宣传产品。 代理商 常被理解错误的“代理商”其真正含义是经授权,甚至拥有代理权的能代表其所代理的公司做承诺的代理人。 海外经销商 海外经销商是从出口商手中购买货物(通常以很低的折扣购买)然后转手卖出获利的商人。海外经销商一般会对产品提供支持和服务,这样就减轻了出口商相应的责任。 国外零售商 公司也会直接将产品卖给海外零售商,虽然在这样的交易中,产品一般仅限于消费品。这种方式主要依赖于和国外零售商直接打交道的巡回推销员。 直销给用户 美国公司可能将自己的产品或服务直接卖给国外的用户。买家可能是国外政府机构,例如医院等。 进口 一个国家进口就意味着另一个国家出口。进口就是产品或服务被其他国家的买家购买的过程,意思与出口刚好相反。

翻译和答案571011

Unit5元素周期表 1.随着对原子的描述越来越详尽,我们发现自己处于进退两难之地。涉及着100 种元素,我们怎样使这些元素保持连续性。一种方法是用元素周期表,周期表把原子信息列成表。它记录着一种元素含有多少质子和电子,它使我们可以计算出大多数元素同位素的中子数。周期表也存有每种元素的电子排列情况。周期表最不寻常的是它的发展是在人们还不知道原子中含有质子和中子之前。 2.道尔顿提出了他的原子模型后不久(一种不可再分的粒子,它的质量取决于 它的性质),化学家开始根据原子质量来排列元素。当得出这种元素表,科学家们观测到元素的规律。例如,那些出现在特定的位置重的元素有某些相似性,这一观点已经越来越明显。当时已知的约60种元素中,第二种和第九种元素表现出相似性,第三种与第十种元素,第四种与第十一种元素也都具有相似的性质。 3.1869年,门捷列夫,一个俄国化学家,提出了他们的元素周期表。他列表时 考虑到原子质量和元素某种特性的周期性。这些元素主要是按原子质量递增的顺序排列的。在特别情况下,门捷列夫把较重的元素放在较轻元素之前。 他这样做是为了在相同列上的元素有相似的化学性质。比如,他把蹄(原子质量=128)放在碘(原子质量=127)之前,因为蹄的性质和硫及硒相似,而碘的性质和氯及溴相似。 4.门捷列夫i在他的周期表中列了许多气体,在他的周期表中留下了一些空格, 他非但没有将那些空格看成缺憾,反而大胆地预测还存在着未被发现的元素。而且,他还预测了许多未知元素的性质。在接下来的几年里,许多气体被填充在新发现的元素中。这些元素的性质通常和门捷列夫预测的非常接近。这些伟大创新的预测使门捷列夫的元素周期表被广泛接受。 5.我们都知道,一种元素的性质主要取决于原子最外层能级上的电子数。Na 在它的最外层能级(第三层)有一个电子,Li原子在它的最外层(第二层)有一个单独的电子。Na和Li的化学性质相似。He和Ne原子已将所有能级排满,它们性质也相似,就是不容易发生化学反应。很明显,不仅具有相似性电子构型(排列)的原子有相似的化学性质,而且,某种电子排列会比其他的排列更稳定。 6.在门捷列夫的元素周期表中,大多数情况下元素是按照原子质量排列的。这 种排列也揭示了元素化学的周期性。因为电子数决定了元素的化学性质,所以电子数也应该决定元素在周期表中的位置。在现代元素周期表中,元素是按照原子序数来排列的。注意,这个数表明在一种元素的中性原子中有多少质子和中子。现代元素周期表,根据原子序数的递增而排列的,而门捷列夫周期表是以原子质量的递增来排列的,通常原子序数的增加是与原子质量的增加同步的。在特殊情况下,原子质量落后于原子序数,因为原子质量是质子和中子质量的而加和,故原子质量并不完全随原子序数增加而增加。有可能一种较低原子序数的原子有更大的原子质量。因此可以在元素周期表上看出来。Ar原子的质量比k原子的质量重。Te原子比I原子质量重。 7.现代元素周期表的竖列叫做族。每一族的元素在最外层能级上有相同的电子 数,因而有相反的化学性质,水平的行叫做周期。每一新周期预示着主电子能级的开始。例如,na从第三行开始。它的最外电子层是第三层第一个电子,因为每一行就开始了一个新的能级,所以我们可以从上到下预测原子的大

相关文档