问题 选择题

短周期元素甲、乙、丙、丁、戊五种元素在元素周期表中的位置如右图所示,其中戊是同周期中原子半径最小的元素。下列有关判断正确的是(  )

A.最外层电子数:甲>乙>丙>丁>戊

B.简单离子的离子半径:戊>丁

C.含有丁元素的酸有多种

D.乙的氢化物多种多样,丙、丁、戊的氢化物各有一种

答案

答案:C

第一周期只有两种元素,而短周期为前三周期,故甲、乙、丙所在周期为第二周期,戊元素原子半径最小,故为第三周期第ⅦA族,即氯元素,由此推知甲、乙、丙、丁分别为B、C、N、S。甲、乙、丙、丁、戊五种元素原子最外层电子数分别为3、4、5、6、7,故A错误;核外电子数相同的简单离子,其离子半径随核电荷数的增加而减小,B错误;丁元素为S,含有S的酸有硫酸、亚硫酸、氢硫酸、硫氰酸等,C正确;氮的氢化物有NH3、N2H4,D错误。

完形填空

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

小题1:   You probably think you will never be a top student, this is not necessarily so, however. Anyone can become a better student he or she wants to . Here’s how:

Plan your time carefully. When planning your week, you should make a list of things that you have to do. After making this list , you should make a plan of your time. First, your time for eating, sleeping, dressing, etc. Then decide a good, regular time for studying.  小题2: A weekly plan may not work out all your problems, but it will push you to realize what is happening to your time.

Find a good place to study. Look around the house for a good study place. Keep this space, which may be a desk or simply a corner of your room, free of everything but study materials. No game, radio, or television! When you sit down to study, concentrate on your subject.

Make good use of your time in class.  小题3:  Really listening in class means less work later. Taking notes will help you remember what the teacher says.

Study regularly. When you get home from school, go over your notes. Review the important points that your teacher is going to discuss the next day, read that material.   小题4: If you do these things regularly ,the material will become more meaningful, and you will remember it longer.

Develop a good attitude to tests. The purpose of a test is to show what you have learned about a subject. They help you remember your new knowledge. The world won’t end if you don’t pass a test, so don’t be over-worried.

小题5:  You will probably find many others after you have tried these

A.Don’t forget to set aside enough time for entertainment.

B.Listen to everything the teacher says.

C.No one can become a top student unless he or she works hard..

D.Maybe you are an average student.E. This will help you understand the next class.

F. Make full use of time to take notes of what the teacher says in class.

G. There are other methods that might help you with your studying

填空题