问题 填空题

(10分)已知A、B、C、D、E是短周期的5种元素,它们的原子序数依次增大。A元素原子形成的离子核外电子数为零;C、D、E三种元素的最高价氧化物对应水化物之间可以两两反应;A与C同主族;B与E同主族;E的单质为黄色晶体,易溶于二硫化碳。

(1)请写出B、D元素的名称:B              ,D              

(2)画出C元素的离子结构示意图                             

(3)写出D的单质与C的最高价氧化物对应水化物之间反应的离子方程式

                                                              

(4)A、B、C三种元素形成的化合物所含的化学键类型为                       

(5)B、C、D三种元素的离子半径由大到小的排列顺序为                  (用离子符号表示)。

答案

(1)B:氧、 D:铝(各1分)          (2)    (2分)

(3)2A1 +  2OH+ 2H2O = 2AlO2 + 3H2↑(2分)

(4)离子键、共价键(各1分)                    (5)O2>Na> Al3+  (2分)

考查元素周期表的结构、原子核外电子的排布规律及元素周期律的应用。A元素原子形成的离子核外电子数为零,所以A是氢元素。E的单质为黄色晶体,易溶于二硫化碳,则E是单质硫。B与E同主族,所以B是氧元素。C、D、E三种元素的最高价氧化物对应水化物之间可以两两反应,因此一定有铝元素。A与C同主族,且C的原子序数等于氧元素的,所以C是钠元素,则D是铝元素。核外电子排布相同的微粒,其微粒半径随原子序数的增大而减小,所以B、C、D三种元素的离子半径由大到小的排列顺序为O2>Na> Al3+

名词解释
问答题

Exactly where we will stand in the long war against disease by the year 2050 is impossible to say. (46) But if developments in research maintain their current pace, it seems likely that a combination of improved attention to dietary and environmental factors, along with advances in gene therapy and protein targeted drugs, will have virtually eliminated most major classes of disease.

From an economic standpoint, the best news may be that these accomplishments .could be accompanied by a drop in health-care costs. (47) Costs may even fall as diseases ’are brought under control using pinpointed, short-term therapies now being developed. By 2050 there will be fewer hospitals, and surgical procedures will be largely restricted to the treatment of accidents and other forms of trauma. Spending on nonacute care, both in nursing facilities and in homes, will also fall sharply as more elderly people lead healthy lives until close to death.

One result of medicine’s success in controlling disease will be a dramatic increase in life expectancy. (48) The extent of that increase is a highly speculative matter, but it is worth noting that medical science has already helped to make the very old (currently defined as those over 85 years of age) the fastest growing segment of the population. Between 1960 and 1995, the U.S. population as a whole increased by about 45%, while the segment over 85 years of age grew by almost 300%. (49) There has been a similar explosion in the population of centenarians, with the result that survival to the age of 100 is no longer the newsworthy feat that it was only a few decades ago. U.S. Census Bureau projections already forecast dramatic increase in the number of centenarians in the next 50 years: 4 million in 2050, compared with 37, 000 in 1990.

(50) Although Census Bureau calculations project an increase in average life span of only eight years by the year 2050, some experts believe that the human life span should not begin to encounter any theoretical natural limits before 120. years. With continuing

(46) But if developments in research maintain their current pace, it seems likely that a combination of improved attention to dietary and environmental factors, along with advances in gene therapy and protein targeted drugs, will have virtually eliminated most major classes of disease.