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问题 填空题

（1）用化学符号表示：2个氮分子______；1个钠离子______．

（2）元素周期表是学习和研究化学的重要工具．如图是元素周期表的一部分．

①查出碳的相对原子质量为______，原子序数为13的元素符号为______．

②表中不同种元素最本质的区别是______．

族

周期

ⅠA      0
11H

1.008

ⅡAⅢAⅣAⅤAⅥAⅦA2He

4.023

23Li

6.991

4Be

9.012

5B

10.51

6C

12.02

7N

14.01

8O

16.00

9F

19.00

10Ne

20.08

311Na

22.96

12Mg

24.31

13Al

26.98

14Si

28.09

15P

30.97

16S

32.00

17Cl

35.45

18Ar

39.95

答案

（1）2个氮分子就是直接在氮气的化学式前面加2；1个钠离子带一个单位正电荷；故答案为：2N2 ；Na+

（2）根据元素周期表中所给信息，从表中查出碳的相对原子质量为 12.02，原子序数为13的元素符号为 Al．故答案为：12.02，Al

②不同种元素最本质的区别是质子数不同．故答案为：质子数不同

单项选择题

What’s your earliest childhood memory Can you remember learning to walk Or talk The first time you heard thunder or watched a television program Adults seldom (1) events much earlier than the year or so before entering school, (2) children younger than three or four (3) retain any specific, personal experiences.

A variety of explanations have been (4) by psychologists for this "childhood amnesia". One argues that the hippo-campus, the region of the brain which is (5) for forming memories, does not mature until about the age of two. But the most popular theory (6) that, since adults don’t think like children, they cannot (7) childhood memories. Adults think in words, and their life memories are like stories or (8) one event follows (9) as in a novel or film. But when they search through their mental (10) for early childhood memories to add to this verbal life story, they don’t find any that fit the (11) It’s like trying to find a Chinese word in an English dictionary.

Now psychologist Annette Simms of the New York State University offers a new (12) for childhood amnesia. She argues that there simply aren’t any early childhood memories to (13) . According to Dr. Simms, children need to learn to use someone else’s spoken description of their personal (14) in order to turn their own short-term, quickly forgotten (15) of them into long term memories. In other (16) , children have to talk about their experiences and hear others talk about (17) — Mother talking about the afternoon (18) looking for seashells at the beach or Dad asking them about their day at Ocean Park. Without this (19) reinforcement, says Dr. Simms, children cannot form (20) memories of their personal experiences.

4（）

A.refuted

B.defied

C.proposed

D.witnessed
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单项选择题

若有定义：char *st="how are you";下列程序段中正确的是( )。

A．char a[11], *p; strcpy(p=a+1,&st[4]);

B．char a[11]; strcpy(++a, s;

C．char a[11]; strcpy(a, s;

D．char a[], *p; strcpy(p=&a[1],st+2);
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