问题 填空题

(8分)下表是元素周期表的一部分。表中所列的字母分别代表一种化学元素。

a  
b   cdef 
ghij klm
n      o          
试回答下列问题:

(1)请写出元素O的基态原子电子排布式

                                   

(2)第三周期8种元素按单质熔点高低的顺序如右图,其中序号“8”代表  

(填元素符号);其中电负性最大的是          (填右图中的序号)。

(3)由j原子跟c原子以1 : 1相互交替结合而形成的晶体,晶型与晶体j相同。两者相比熔点更高的是       (填化学式),试从结构角度加以解释:                    

                                                                                                                                          

答案

(1)1s22s22p63s23p63d64s2(2分)   (2) Si;    2 (2分)   

(3)SiC;(1分);因SiC晶体与晶体Si都是原子晶体,由于C的原子半径小,SiC中C-Si键键长比晶体Si中Si-Si键长短,键能大,因而熔沸点高。(3分)

(1)根据元素的位置可判断,O是铁元素。因此根据构造原理可知,核外电子排布式为1s22s22p63s23p63d64s2

(2)第三周期中,熔点最高的是原子晶体硅,即8号是Si。非金属性越强,电负性越大,所以。所以电负性最大的是Cl,Cl的熔点仅比Ar的高,所以应该是2号。

(3)两种元素分别是C和Si,形成的SiC是原子晶体。因SiC晶体与晶体Si都是原子晶体,由于C的原子半径小,SiC中C-Si键键长比晶体Si中Si-Si键长短,键能大,因而熔沸点高。

阅读理解

阅读理解

     Dog walkers provide a 20 to 60minute daily walk for a client's(客户)dog, making sure the dog

answers the call of nature and gets proper exercise. They often walk more than one dog at a time. Some

walkers work for dogwalking services, especially when starting out. Others have their own businesses,  

and build by word of mouth and advertising. Dog walkers often work parttime, and some provide other

services like pet sitting or transporting.

     In New York, dog walkers usually earn about $25 an hour. If you work for a dogwalking business,

you may earn less; if you are on your own dealing with several dogs at the same time, it may be more.

What do you have to do to be a dog walker?

     First, have a real love of dogs, and have a good knowledge of how to get on with dogs. Try calling

dogwalking services to find out about openings. If you're on your own, you'll need to network and market yourself. You might advertise your services in pet offices, grooming businesses, or neighborhood papers.

You will need business cards and a mobile phone, and have good references and a clean background.

You'll also have to deal with taxes and insurance. You should be physically fit, friendly, neatly dressed

and extremely dependable. Many dog walkers are bonded(被担保的)and insured, and this is a definite

selling point to clients.

     Of course, you will be cleaning up dog waste! You will also be outside in all kinds of weather. You

may have to deal with dogs that don't like each other, and difficult owners. It's also an upanddown kind

of business-clients can come and go.

     For pet lovers, spending the workday with dogs instead of navigating office politics is its own reward! You are your own boss-you can dress casually, your doggy clients will love you unconditionally, and

you'll get some great exercise!

1. By writing the passage the writer tries to________.

A. introduce you to a job

B. enrich your knowledge about pets

C. advertise for a business

D. tell you more about life in New York

2. The passage offers no information about how to ________ as a dog walker.

A. find a client  B. train a dog

C. get prepared  D. make more money

3. One who wants to ________ may find the passage helpful.

A. take up a weekend job

B. keep a good pet dog

C. make money in his daily spare time

D. be a parttime office worker

4. The fifth paragraph is meant to tell you________.

A. what dogwalking is like

B. why dogwalking is worth trying

C. the unknown part of dogwalking

D. the bad side of dogwalking

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