问题 选择题

今年3月11日,日本发生里氏9.0级特大地震并引发海啸,造成福岛第一核电站发生核泄漏事故.放射性物质中有碘元素的一种原子,它的相对原子质量为131,核内质子数为53.下列叙述正确的是(  )

A.它的核内中子数为53

B.它的核外电子数为78

C.它的核内中子数与质子数之差为25

D.它是一种金属元素

答案

A、已知碘原子核内质子数为53,质子数与中子数之和为131,则中子数是131-53=78;故不正确;

B、在原子中,核内质子数=核外电子数,再根据题意知其核外电子数是53;故不正确;

C、由A分析可知,它的核内中子数为78,因此它的核内中子数与质子数之差为78-53=25,故C正确;

D、由碘元素的名称可知,带“石”字旁,属于非金属元素,故A正确;

故选C.

阅读理解

阅读短文,选择正确答案。

       One morning, the students of Class Three, Grade One are having an English lesson. Mr Zhang finds Li Lei

doesn't listen to him. He goes to Li Lei and has a look. Oh, Li Lei is drawing a boy.

       The teacher asks Li Lei to stand up. "Do you like drawing?" 

       "Yes, Mr Zhang," answers Li Lei. "And I draw very well." 

       "You can draw after class, I think," says the teacher. "You can't draw anything in class." 

       "You are wrong, Mr Zhang. I can draw when I have an Art class. And I like it very much," says Li Lei with

a smile. 

       "You are right. And you must draw one hundred boys before the class is over," says the teacher angrily. 

        After five minutes, Li Lei finishes drawing and puts up his hand. The teacher looks at the picture and asks,

"I ask you to draw one hundred boys. But you draw only two. One is standing at the door and the other is

standing in front of the window. Where are the others?" 

        "The others are sitting in the classroom. You can't see them," answers Li Lei.

1. What is Mr. Zhang? [ ]

A. He is a Chinese teacher.

B. He is a Maths teacher.

C. He is an Art teacher.

D. He is an English teacher.

2. The underlined sentence in Paragraph 4 means that             . [ ]

A. the boy can draw something

B. the boy can't draw in art class

C. the boy can't draw in an English class

D. the boy likes drawing after class

3. How many boys does Li Lei draw? [ ]

A. Two.

B. Ten.

C. One.

D. One hundred.

4. What does Li Lei like? [ ]

A. Playing football.

B. Drawing.

C. Studying.

D. Watching TV.

5. How many boys does Mr Zhang ask Li Lei to draw? [ ]

A. Two.

B. One hundred.

C. Three.

D. One.

单项选择题