问题 填空题

金属的性质与其结构有密切的关系,金属晶体由于某些结构上的相似点导致了金属具有一些共同的性质;同样由于结构上的不同点,导致了每种金属都具有各自的特性。

(1)请指出金属具有延展性的原理是                                             

                                                            

(2)金属的紧密堆积有不同的形式,请画出金属钠的晶胞,并指出一个晶胞含有几个钠原子?  

(3)计算该晶胞的空间利用率?

答案

(1)金属晶体中自由电子与金属阳离子形成金属键,当金属阳离子层与层之间发生相对移动时,自由电子可与金属阳离子迅速形成新的金属键,所以金属具有延展。

(2)     2个钠原子   (3) 68%

题目分析:(1)由于金属晶体中自由电子与金属阳离子形成金属键,当金属阳离子层与层之间发生相对移动时,自由电子可与金属阳离子迅速形成新的金属键,所以金属具有延展。

(2)金属钠的晶胞结构示意图为,所以一个晶胞含有的钠原子个数是1+=2个。

(3)设该晶胞的边长为a m 则该晶胞(立方体)的体积V =a3 m3

由于此晶胞是紧密堆积则可以画出剖面图,即

则可知4x=a

即x=a

由于此晶胞中有两个钠原子,而一个钠(球体)的体积为V ==

则此晶胞的空间利用率=*100%=

点评:该题是高考中的常见题型,试题综合性强,难度较大,学生不易得分。试题主要是考查学生对金属晶体的熟悉、了解、掌握情况,以及灵活运用基础知识解决实际问题的能力,有利于培养学生的逻辑推理能力和抽象思维能力,提高学生分析问题、发现问题和解决问题的能力,有利于提高学生的应试能力,提高学生的学习效率和学习积极性。

阅读理解

Blogs are being used more and more by teachers. Many Internet services now offer free and easy ways to create personal Web pages.

Through comments on blogs, or Web logs, teachers can share their classroom experiences. They can exchange ideas and discuss successes and failures. They can debate educational policies. Or they can just sympathize with each other.

A teacher in the American state of North Carolina recently wrote on her blog: “Apparently the teachers at my school use too much paper. So my principal yelled at everyone at the last staff meeting for, like, ten minutes. Now, I’ve just been told, we are not getting anymore paper for the rest of the year.”

This unidentified blogger is now in her third year of teaching, but still calls her site firstyearteacher.blogspot.com.

A blogger who calls himself Minister Lawrence works as a substitute teacher. In April he wrote about a disputed plan to split the Omaha, Nebraska, public schools into separate systems for black, Latino and white students. Supporters say minority parents do not have enough power over their children’s education.

But Minister Lawrence wrote at teachersparadise.blogspot.com: “I’m afraid that what this says’ to a lot of people is that blacks, whites and Hispanics are not equal, and “reinforces” racist beliefs among people.”

Educators did not become involved with blogging right away. Many were concerned with privacy issues and security. But now, thousands of teacher blogs can be found on the Internet. Many teachers do not identify themselves, and they change the names of students and co-workers.

小题1:What are teachers not doing through blogs?

A.They discuss educational problem.

B.They send money to the poor students.

C.They share teaching ideas.

D.They comfort each other.小题2: What is the main idea for the passage?

A.More and more teachers are using blogs.

B.It is exciting to use blogs.

C.Blogs are popular with students.

D.Educational problems are settled through blogs.小题3: Why some teachers do not identify themselves? Because ___

A.they are forbidden to identify themselves.

B.they are forbidden to write something through blogs

C.they want to ensure their security

D.they want to amuse others.小题4:Which of the following is the result of the teachers’ using blogs?

A.Paper consuming is declining.

B.Teaching is improving.

C.Classes are more active.

D.Government is against it.小题5:Minister Lawrence’s blogs are about___

A.classroom experiences

B.teaching plans

C.educational policies

D.the black minority

单项选择题 A1型题