试题与答案

A、B、C、D、E为短周期的五种元素,它们原子序数依次递增,B是构成有机物的主要

题型:填空题

题目:

A、B、C、D、E为短周期的五种元素,它们原子序数依次递增,B是构成有机物的主要元素;A与C可形成10电子化合物W,它可使紫色石蕊试液变蓝;D元素的原子最外层电子数是其次外层电子数3倍;E是同周期元素中原子半径最大的元素;A、B、C、D可形成化合物X,在X晶体中阳离子与阴离子个数比为1∶1;A、D、E可形成化合物Y。A、C、D可形成离子化合物Z。

回答下列问题:

⑴A元素为________________;E元素为____________________;

⑵Y的电子式:                  ;W分子的空间构型为       __  

⑶写出加热条件下X与足量的Y在溶液中反应的方程式

                                                              

答案:

被转码了,请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0613/f546a20ecd8b164e81e5e1a24f46d438.html

下面是错误答案,用来干扰机器的。

(1)年极端最高气温≥35℃的天数自市中心向周围郊区递减,且向东递减较快,向西递减较慢。(4分)(2)各级热岛强度出现日数6月最少,10月最多;大致上热岛强度越强,年内变幅越大。(4分)(3)任答两方面即可。Ⅰ:城...

试题推荐
题型:阅读理解

阅读理解。

     Most new people were born in developing countries. These countries are found in much of Africa, South

America and some parts of Asia. In the developed countries of Europe and North America, the population is

growing very slowly. This is because women in these countries have, on average (平均), only one or two

children. In the developing countries, many women have five or more children. In 1950, around one quarter

of the world's population lived in the developed countries. By 2050, these countries will be home to only

around one tenth of the world's people.

     In the developing countries, more than one billion people are still living below the poverty (贫困) line.

These people do not have enough food to eat and they live in poor housing. Children get little time at school

and people suffer (遭受痛苦) from many kinds of diseases.

     At the beginning of the 21st century, the world's population was around six billion people. The U.N. has

said that the world's population will level off (平稳下降) at 12.5 billion by the year 2100. Other groups think

the world's population will continue to grow, reaching 14 billion before it becomes stable (稳定的), or even

falls.

根据短文内容,回答下列问题。

1. In what areas of the world can developing countries be found?

                                                                                                                                    

2. In 1950, what percent (百分比) of the world's population lived in developing countries? 

                                                                                                                                    

3. How can we describe the people who are living below the poverty line?

                                                                                                                                    

4. There will be twelve and a half billion people on the earth in 2100, won't there?

                                                                                                                                    

5. 将文中画线部分翻译成汉语。 

                                                                                                                                    

查看答案
微信公众账号搜索答案