问题 选择题

根据钫在周期表中的位置预言其性质,其中不正确的是(   )

A.在碱金属中原子半径最大

B.其单质的熔点比金属钠的熔点低

C.氧化物对应的水化物是极强的碱

D.在空气中燃烧时生成氧化物Fr2O

答案

答案:D

IA族:氢、锂、钠、钾、铷、铯、钫。

同主族,由上到下,原子半径增大,故A正确;

金属族,由上到下,熔点减低,故B正确;

同主族,由上到下,原子的失电子能力逐渐增强,则最高价氧化物对应水化物的碱性增强,NaOH已是强碱,故C正确;

同主族,由上到下,原子的失电子能力逐渐增强,金属单质的活泼性增强,Na在空气中燃烧时已能生成过氧化物Na2O2,故D错误;

完形填空

完形填空(共 15小题,每小题 1 分,满分15分)

阅读下面短文,从每小题A、B、C三个选项中,选出可以填入空白处的最佳选项,并将其字母标号填入题前的括号内。

A well-dressed man came into a famous jewellery (首饰)shop. He explained that he wished to buy a pearl(珍珠)for his wife’s birthday and that the  16  did not matter since business had been very good for him that year. After examin;ing a number of beautiful and valuable pearls, he chose a nice black one that _17_ $5000. He paid for that pearl , shook hands with the jeweler and left.

A few days later the man returned and said his wife had liked that pearl _18_ that she wanted another one just like it. It had to be exactly the _19_ size and quality as she wanted a pair of earrings made. “Can you give me any advice on _20_ to get such a pearl?” said the man. The jeweler replied , “I would say it’s _21_ to find an exact one like that pearl.”

The rich man _22_ the jeweler to advertise in the newspaper, and offered $25.000 for that matching pearl. Many people answered that ad, _23_ nobody had a pearl that was just right. Just when the jeweler had _24__  hope, an old lady came in. To his _25_ , she took a wonderful pearl from her handbag. “I don’t like to sell it, ” she said _26_. “I inherited (继承)it from my mother, and my mother inherited from _27_, but now I really need money.”

The jeweler was quick to pay her _28_ she changed her mind. Then he called the rich man’s hotel to tell the good _29_ to him. The rich man, however, was _30_ to be found. He had fled with the old woman a few more minutes before.

小题1: A. size               B. shape             C. price

小题2:A. spent               B. cost              C. took

小题3: A. a little              B. so much           C. at all

小题4: A. same               B. different           C. common

小题5:A. what               B. why              C. how

小题6: A. possible            B. easy               C. impossible

小题7: A. let                 B. make              C. asked

小题8: A. so                 B. but                C. and

小题9: A. found out           B. given up            C. come up with

小题10: A. disappointment      B. surprise             C. fear

小题11:A. happily             B. loudly             C. sadly

小题12:A. mine               B.his                 C. hers

小题13: A. when               B. before             C. after

小题14: A. news               B. advice             C. way

小题15: A. somewhere          B. anywhere           C. nowhere

单项选择题