问题 选择题

下列四种元素中,其单质氧化性最强的是(  )

A.原子含未成对电子最多的第二周期元素

B.原子最外层电子排布为2s22p4的元素

C.位于周期表中第三周期ⅢA族的元素

D.原子最外层电子排布为3s23p3的元素

答案

A、原子含未成对电子最多的第二周期元素是N元素,氮气的化学性质稳定;

B、原子最外层电子排布为2s22p4的元素是O元素,

C、位于周期表中第三周期ⅢA族的元素是Al元素,

D、原子最外层电子排布为3s23p3的元素是P元素,

非金属性O>N>P,氧气的氧化性最强,

故选B.

完形填空

第二节(共5小题;每小题2.5分,满分12.5分)

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。

People know the dangers of fires. It’s good for a family to learn how to prepare for a fire. Here are some suggestions.

Put a smoke alarm in the house. The alarm makes a loud sound.   71    

Make escape plans. They should know all the ways out of the house. If there is a fire, everyone follows the plan to get out.   72  

Practise for a fire. They do fire practice because they teach children about fire safety.Everyone in the family should know the following fire rules:

Don't open a hot door! The fire can grow more quickly if you open the door. 73   Smoke can be more dangerous than fire. The best air is near the floor because smoke rises.

What will you do if your hair or clothes start to burn? First, don’t run! The fire burns faster because of more air. Drop! Fall to the floor. Then roll!    74    Put a blanket around you to keep air away from the fire that may still be on you.

There are many possible causes for fires.    75    If there is a fire, don’t forget to call 119 for help.

A.Turning over and over will make the fire go out.

B.Smoke from a fire causes the alarm to go off.

C.The cleanest air is found at the top.

D.Stay close to the floor!E. A wise family is ready all the time.

F. Make sure all the windows can be opened easily.

G. Do not go back to the house for any reason.

单项选择题