问题 选择题

与Li<Na<K<Rb<Cs的变化规律不符合的是

A.与水或酸反应置换氢气越来越剧烈

B.金属性由弱到强

C.对应阳离子的氧化性由弱到强

D.原子半径由小到大

答案

答案:C

题目分析:同主族自上而下,原子半径逐渐增大,金属性逐渐增强,相应金属阳离子的氧化性逐渐减弱,所以选项C不正确,应该是对应阳离子的氧化性由强到弱,其余选项都是正确的,答案选C。

点评:该题是高考中的常见题型,属于基础性试题的考查,主要是考查学生灵活运用元素周期律解决实际问题的能力,有助于培养学生的逻辑推理能力,提高学生的学习效率。

单项选择题
阅读理解

阅读理解。

     The energy crisis (危机) has made people aware of how the careless use of the earth's energy has brought

the whole world to the edge of disaster. The over-development of motor transport, with its increase of more

cars, more traveling, has contributed to the near-destruction of our cities and the pollution not only of local air

but also of the earth's atmosphere. 

     Our present situation is unlike natural disasters of the past. Worldwide energy use has brought us to a state

where long-range planning is vital. What we need is not a continuation of our present serious state, which

endangers the future of our country, our children, and our earth, but a movement forward in order to work

rapidly and effectively on planetary problems.

     This country has been falling back under the continuing exposures of loss of morality and the revelation (揭

露) that lawbreaking has reached into the highest place in the land. There is a strong demand for morality to

turn for the better and for some devotion that is vast enough and yet personal enough to enlist the devotion of

all. In the past it has been only in a way in defense of their own country and their own benefits that people have

been able to devote themselves wholeheartedly.

     This is the first time that we have been asked to defend ourselves and what we hold dear in cooperation

with all the other people of this planet, who share with us the same endangered air and the same endangered

oceans. There is a common need to reassess our present course, to change that course and to employ new

methods through which the world can survive. This is a priceless opportunity.

     To grasp it, we need a widespread understanding of nature if the crisis we and the world are facing is no

passing inconvenience, no byproduct of the ambitions of the oil-producing countries, no environmentalists'

only fears, no byproduct of any present system of government. What we face is the result of the invention

of the last four hundred years. What we need is a transformed life style. This new life style can flow directly

from science and technology, but its acceptance depends on a sincere devotion to finding a higher quality of

life for the world's children and future generation.

1. Which of the following has nearly destroyed our cities?[ ]

A. The loss of beliefs and ideas. 

B. More of law-breaking.

C. Natural di8asters in many areas.

D. The rapid growth of motors.

2. By comparing past problems with present ones, the author draws our attention to the _____. [ ]

A seriousness of this crisis

B. ineffectiveness of laws

C. similarity of the past to the present

D. hopelessness of the situation

3. Which of the following is used as an example to show the loss of morality? [ ]

A. Disregard for law.

B. Lack of devotion.

C. Lack of understanding.

D. Destruction of cities.

4. The author wrote the passage in order to _____. [ ]

A. make a recommendation for a transformed life style 

B. limit ambitions of the people of the whole world

C. demand devotion to nature and future generation

D. encourage awareness of the decline of morality