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结合下列原子结构示意图和氦元素的元素周期表信息回答以下问题。

（1）在A-E五个结构示意图中，达到稳定结构原子的是_________；属于同种元素的是___________。

（2）写出B和E两种元素形成化合物的化学式（用B、E表示）_______。

（3）氦元素的元素符号为______；相对原子质量为_______。

答案

（1） AC   DE ；（2）EB2；（3）He 4.00

题目分析：元素周期表是化学的重要工具，本题微扰元素周期表及元素的相关性质展开，难度不大，但如不仔细审题会出错。首先从A-E等5个结构示意图进行分析，核内质子数就是原子序数，故A就是氦原子，B是氟原子，C是氖原子，D是镁离子（注意其核外电子数少于核内质子数），E是镁原子。因此，我们不难填出达到稳定结构的原子是AC，属于同种元素，即核内质子数相等的，答案是DE.要解答（2）必须注意化学家，E代表的是金属镁，是+2价，而B代表的是非金属氟，呈现的是-1价，故答案应是EB2。解答（3）比较简单，相对原子质量为图片上所示的4.00.

点评：会通过观察和推断，运用基础知识解题。

阅读理解
任务型阅读。
Countries In   1     countries  In rich countries 
Phenomena (现象)A lot of people in poor countries can not eat   2 food.People in rich countries eat too much.
Children are hungry.Many people have to  3  weight by going on a diet or  4  
Difficult problems
The land is too poor for plants to     5  The air and the rivers are  6  .
There is a lot of   7  and people  in the roads
and the streets.
Solutions (解决方法)People should learn how to  8    their land
and find the water.		Make the air and the river   9     
  10  more houses.
     The world is divided into(被分为)two important parts. One half of the world is rich and the other half
is poor. In the poor part, a lot of people never get enough to eat. In the rich part, a lot of people eat too
much. In one part, children are hungry and in the other, a lot of people are fatter and fatter and have to go
on diets or do some exercise to lose weight. For example, a dog or a cat in North America eats better
than a child in the poorer countries.
     The poor countries have some difficult problems. Sometimes the land is too poor to grow anything on.
The land can get better, but people have to do a lot of things first. More experts (专家)should go there to
teach people how to enrich their land and how to find water.
     But rich countries have problems, too. They are not always pleasant places to live in. Sometimes the
air is too dirty to breathe (呼吸)and the rivers are too dirty to swim in or to take water. The roads and the
streets are full of people and buses. Cars usually move very slowly. Noise is terrible. A lot of people do
not have houses to live in. People must do something about these problems. We should do something to
make the air and the rivers clean and build more houses. But it will take a long time.
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